Tag: OneFS

In this article, we’ll take a quick peek at the new PowerScale F210 hardware platform that was released last week. Here’s where this new node sits in the current hardware hierarchy:

The PowerScale F210 is an entry level, performant, all-flash platform that utilizes NVMe SSDs and a single-socket CPU 1U PowerEdge platform with 128GB of memory per node.  The ideal use cases for the F210 include high performance workflows, such as M&E, EDA, AI/ML, and other HPC applications.

An F210 cluster can comprise between 3 and 252 nodes, each of which contains four 2.5” drive bays populated with a choice of 1.92TB, 3.84TB, 7,68TB TLC, or 15.36TB QLC enterprise NVMe SSDs. Inline data reduction, which incorporates compression, dedupe, and single instancing, is also included as standard and enabled by default to further increase the effective capacity.

The F210 is based on the 1U R660 PowerEdge server platform, with a single socket Intel Sapphire Rapids CPU.

The node’s front panel has limited functionality compared to older platform generations and simply allows the user to join a node to a cluster and display the node name once the node has successfully joined.

An F210 node’s serial number can be found either by viewing /etc/isilon_serial_number or via the following CLI command syntax. For example:

# isi_hw_status | grep SerNo
  SerNo: HVR3FZ3

The serial number reported by OneFS will match that of the service tag attached to the physical hardware and the /etc/isilon_system_config file will report the appropriate node type. For example:

# cat /etc/isilon_system_config
PowerScale F210

Under the hood, the F210’s core hardware specifications are as follows:

Attribute	F210 Spec
Chassis	1RU Dell PowerEdge R660
CPU	Single socket, 12 core Intel Sapphire Rapids 4410Y @2GHz
Memory	128GB Dual rank DDR5 RDIMMS (8 x 16GB)
Journal	1 x 32GB SDPM
Front-end network	2 x 100GbE or 25GbE
Back-end network	2 x 100GbE or 25GbE
NVMe SSD drives	4

The node hardware attributes can be gleaned from OneFS by running the ‘isi_hw_status’ CLI command. For example:

f2101-1# isi_hw_status -c

  HWGen: PSI

Chassis: POWEREDGE (Dell PowerEdge)

    CPU: GenuineIntel (2.00GHz, stepping 0x000806f8)

   PROC: Single-proc, 12-HT-core

    RAM: 102488403968 Bytes

   Mobo: 0MK29P (PowerScale F210)

  NVRam: NVDIMM (NVDIMM) (8192MB card) (size 8589934592B)

 DskCtl: NONE (No disk controller) (0 ports)

 DskExp: None (No disk expander)

PwrSupl: PS1 (type=AC, fw=00.1B.53)

PwrSupl: PS2 (type=AC, fw=00.1B.53)

While the actual health of the CPU and power supplies can be quickly verified as follows:

# isi_hw_status -s

Power Supplies OK

Power Supply PS1 good

Power Supply PS2 good

CPU Operation (raw 0x881B0000)  = Normal

Additionally, the ‘-A’ flag (All) can also be used with ‘isi_hw-status’ to query a plethora of hardware and environmental information.

Node and drive firmware versions can also be checked with the ‘isi_firmware_tool’ utility. For example:

f2101-1# isi_firmware_tool --check

Ok

f2101-1# isi_firmware_tool --show

Thu Oct 26 11:42:32 2023 - Drive_Support_v1.46.tgz

Thu Oct 26 11:42:58 2023 - IsiFw_Package_v11.7qa1.tar

The internal layout of the F210 chassis with the risers removed is as follows:

The cooling is primarily driven by four dual-fan modules, which can be easily accessed and replaced as follows:

Additionally, the power supplies also contain their own air flow apparatus, and can be easily replaced from the rear without opening the chassis.

For storage, each PowerScale F210 node contains four NVMe SSDs, which are currently available in the following capacities and drive styles:

Standard drive capacity	SED-FIPS drive capacity	SED-non-FIPS drive capacity
1.92 TB TLC	1.92 TB TLC	–
3.84 TB TLC	3.84 TB TLC	–
7.68 TB TLC	7.68 TB TLC	–
15.36 TB QLC	Future availability	15.36 TB QLC

Note that a 15.36TB SED-FIPS drive option is planned for future release. Additionally, the 1.92TB drives in the F210 can also be short-stroke formatted for node compatibility with F200s containing 960GB SSD drives. More on this later in the article.

The F210’s NVMe SSDs populate the drive bays on the left front of the chassis, as illustrated in the following front view (with bezel removed):

Drive subsystem-wise, OneFS provides NVMe support across PCIe lanes, and the SSDs use the NVMe and NVD drivers. The NVD is a block device driver that exposes an NVMe namespace like a drive and is what most OneFS operations act upon, and each NVMe drive has a /dev/nvmeX, /dev/nvmeXnsX and /dev/nvdX device entry  and the locations are displayed as ‘bays’. Details can be queried with OneFS CLI drive utilities such as ‘isi_radish’ and ‘isi_drivenum’. For example:

f2101-1# isi_drivenum
Bay 0   Unit 3      Lnum 0     Active      SN:BTAC2263000M15PHGN   /dev/nvd3
Bay 1   Unit 2      Lnum 2     Active      SN:BTAC226206VB15PHGN   /dev/nvd2
Bay 2   Unit 0      Lnum 1     Active      SN:BTAC226206R515PHGN   /dev/nvd0
Bay 3   Unit 1      Lnum 3     Active      SN:BTAC226207ER15PHGN   /dev/nvd1
Bay 4   Unit N/A    Lnum N/A   N/A         SN:N/A              N/A
Bay 5   Unit N/A    Lnum N/A   N/A         SN:N/A              N/A
Bay 6   Unit N/A    Lnum N/A   N/A         SN:N/A              N/A
Bay 7   Unit N/A    Lnum N/A   N/A         SN:N/A              N/A
Bay 8   Unit N/A    Lnum N/A   N/A         SN:N/A              N/A
Bay 9   Unit N/A    Lnum N/A   N/A         SN:N/A              N/A

As shown, the four NVMe drives occupy bays 0-3, with the remaining six bays unoccupied. These four drives and their corresponding PCI bus addresses can also be viewed via the following CLI command:

f2101-1# pciconf -l | grep nvme
nvme0@pci0:155:0:0:     class=0x010802 card=0x219c1028 chip=0x0b608086 rev=0x00 hdr=0x00
nvme1@pci0:156:0:0:     class=0x010802 card=0x219c1028 chip=0x0b608086 rev=0x00 hdr=0x00
nvme2@pci0:157:0:0:     class=0x010802 card=0x219c1028 chip=0x0b608086 rev=0x00 hdr=0x00
nvme3@pci0:158:0:0:     class=0x010802 card=0x219c1028 chip=0x0b608086 rev=0x00 hdr=0x00

Comprehensive details and telemetry for individual drive are available via the ‘isi_radish’ CLI command using their /dev/nvdX device entry. For example, for /dev/nvd0:

f2101-1# isi_radish -a /dev/nvd0
Drive log page ca: Intel Vendor Unique SMART Log
              Key                              Attribute                                         Field                                                 Value
============================== ======================================== 
(5.0) (4.0)=(171) (0.0)              Program Fail Count                 Normalized Value                                        100
(5.0) (4.0)=(171) (0.1)                                                 Raw Value                                               0
(5.0) (4.0)=(172) (0.0)              Erase Fail Count                   Normalized Value                                        100
(5.0) (4.0)=(172) (0.1)                                                 Raw Value                                               0
(5.0) (4.0)=(173) (2.0)              Wear Leveling Count                Normalized Value                                        100
(5.0) (4.0)=(173) (2.1)                                                 Min. Erase Cycle                                        2
(5.0) (4.0)=(173) (2.2)                                                 Max. Erase Cycle                                        14
(5.0) (4.0)=(173) (2.3)                                                Avg. Erase Cycle                                        5
(5.0) (4.0)=(184) (1.0)              End to End Error Detection Count   Raw Value                                               0
(5.0) (4.0)=(234) (3.0)              Thermal Throttle Status            Percentage                                              0
(5.0) (4.0)=(234) (3.1)                                                 Throttling event count                                  0
(5.0) (4.0)=(243) (1.0)              PLL Lock Loss Count                Raw Value                                               0
(5.0) (4.0)=(244) (1.0)              NAND sectors written divided by .. Raw Value                                               3281155
(5.0) (4.0)=(245) (1.0)              Host sectors written divided by .. Raw Value                                               1445498
(5.0) (4.0)=(246) (1.0)              System Area Life Remaining         Raw Value                                               0
Drive log page de: DellEMC Unique Log Page

              Key                              Attribute                                         Field                                                 Value
============================== ======================================== ======================================================= ==================================================
(6.0)                            DellEMC Unique Log Page                Log Page Revision                                       2
(6.1)                                                                   System Aread Percent Used                               0
(6.2)                                                                   Max Temperature Seen                                    48
(6.3)                                                                   Media Total Bytes Written                               110097292328960
(6.4)                                                                   Media Total Bytes Read                                  176548657233920
(6.5)                                                                   Host Total Bytes Read                                   164172138545152
(6.6)                                                                   Host Total Bytes Written                                48502864347136
(6.7)                                                                   NAND Min. Erase Count                                   2
(6.8)                                                                   NAND Avg. Erase Count                                   5
(6.9)                                                                   NAND Max. Erase Count                                   14
(6.10)                                                                  Media EOL PE Cycle Count                                3000
(6.11)                                                                  Device Raw Capacity                                     15872
(6.12)                                                                  Total User Capacity                                     15360
(6.13)                                                                  SSD Endurance                                           4294967295
(6.14)                                                                  Command Timeouts                                        18446744073709551615
(6.15)                                                                  Thermal Throttle Count                                  0
(6.16)                                                                 Thermal Throttle Status                                 0
(6.17)                                                                  Short Term Write Amplification                          192
(6.18)                                                                  Long Term Write Amplification                           226
(6.19)                                                                  Born on Date                                            06212022
(6.20)                                                                  Assert Count                                            0
(6.21)                                                                  Supplier firmware-visible hardware revision             5
(6.22)                                                                  Subsystem Host Read Commands                            340282366920938463463374607431768211455
(6.23)                                                                  Subsystem Busy Time                                     340282366920938463463374607431768211455
(6.24)                                                                  Deallocate Command Counter                              0
(6.25)                                                                  Data Units Deallocated Counter                          165599450
Log Sense data (Bay 2/nvd0 ) --
Supported log pages 0x1 0x2 0x3 0x4 0x5 0x6 0x80 0x81

SMART/Health Information Log
============================
Critical Warning State:         0x00
 Available spare:               0
 Temperature:                   0
 Device reliability:            0
 Read only:                     0
 Volatile memory backup:        0
Temperature:                    307 K, 33.85 C, 92.93 F
Available spare:                100
Available spare threshold:      10
Percentage used:                0
Data units (512,000 byte) read: 320648767
Data units written:             94732208
Host read commands:             3779434531
Host write commands:            1243274334
Controller busy time (minutes): 33
Power cycles:                   93
Power on hours:                 2718
Unsafe shutdowns:               33
Media errors:                   0
No. error info log entries:     0
Warning Temp Composite Time:    0
Error Temp Composite Time:      0
Temperature 1 Transition Count: 0
Temperature 2 Transition Count: 0
Total Time For Temperature 1:   0
Total Time For Temperature 2:   0

SMART status is threshold NOT exceeded (Bay 2/nvd0 )
NAND Write Amplification: 2.269913, (Bay 2/nvd0 )

Error Information Log
=====================
No error entries found
Bay 2/nvd0  is Dell Ent NVMe SED P5316 RI 15.36TB FW:1.2.0 SN:BTAC226206R515PHGN, 30001856512 blks

                Attr                          Value
=================================== =========================
NAND Bytes Written                  3281155
Host Bytes Written                  1445498

Drive Attributes: (Bay 2/nvd0 )

In contrast, the rear of the F710 chassis contains the power supplies, network, and management interfaces, which are laid out as follows:

The F210 nodes are available in the following networking configurations, with a 25/100Gb ethernet back-end and 25/100Gb ethernet front-end:

Front-end NIC	Back-end NIC	F210 NIC Support
100GbE	100GbE	Yes
100GbE	25GbE	No
25GbE	100GbE	Yes
25GbE	25GbE	Yes

Note that there is currently no support for an F210 Infiniband backend in OneFS 9.7.

These NICs and their PCI bus addresses can be determined via the ’pciconf’ CLI command, as follows:

f2101-1# pciconf -l | grep mlx
mlx5_core0@pci0:23:0:0: class=0x020000 card=0x005815b3 chip=0x101d15b3 rev=0x00 hdr=0x00
mlx5_core1@pci0:23:0:1: class=0x020000 card=0x005815b3 chip=0x101d15b3 rev=0x00 hdr=0x00
mlx5_core2@pci0:111:0:0:        class=0x020000 card=0x005815b3 chip=0x101d15b3 rev=0x00 hdr=0x00
mlx5_core3@pci0:111:0:1:        class=0x020000 card=0x005815b3 chip=0x101d15b3 rev=0x00 hdr=0x00

Similarly, the NIC hardware details and drive firmware versions can be view as follows:

f2101-1# mlxfwmanager
Device #1:
----------
  Device Type:      ConnectX6DX
  Part Number:      0F6FXM_08P2T2_Ax
  Description:      Mellanox ConnectX-6 Dx Dual Port 100 GbE QSFP56 Network Adapter
  PSID:             DEL0000000027
  PCI Device Name:  pci0:23:0:0
  Base GUID:        a088c20300052a3c
  Base MAC:         a088c2052a3c
  Versions:         Current        Available
     FW             22.36.1010     N/A
     PXE            3.6.0901       N/A
     UEFI           14.29.0014     N/A
  Status:           No matching image found

Device #2:
----------
  Device Type:      ConnectX6DX
  Part Number:      0F6FXM_08P2T2_Ax
  Description:      Mellanox ConnectX-6 Dx Dual Port 100 GbE QSFP56 Network Adapter
  PSID:             DEL0000000027
  PCI Device Name:  pci0:111:0:0
  Base GUID:        a088c2030005194c
  Base MAC:         a088c205194c
  Versions:         Current        Available
     FW             22.36.1010     N/A
     PXE            3.6.0901       N/A
     UEFI           14.29.0014     N/A
  Status:           No matching image found

Performance-wise, the new F210 is a relative powerhouse compared to the F200. This is especially true for NFSv3 streaming reads, as can be seen below:

OneFS node compatibility provides the ability to have similar node types and generations within the same node pool. In OneFS 9.7, compatibility between the F210 nodes and the previous generation F200 platform is supported.

Component	F200	F210
Platform	R640	R660
Drives	4 x SAS SSD	4 x NVMe SSD
CPU	Intel Xeon Silver 4210 (Cascade Lake)	Intel Xeon Silver 4410Y (Sapphire Rapids)
Memory	96GB DDR4	96GB DDR5

This compatibility facilitates the addition of individual F210 nodes to an existing node pool comprising three of more F200s if desired, rather creating a F210 new node pool. Despite the different drive subsystem across the two platforms, and the performance profiles above. Because of this, however, the F210/F200 node compatibility is slightly more nuanced, and the F210 NVMe SSDs are considered ‘soft restriction’ compatible with the F200 SAS SSDs. Additionally, the 1.92TB is the smallest capacity option available for the F210, and the only supported drive configuration for F200 compatibility.

In compatibility mode the 1.92Tb drives will be short stroke formatted, resulting in a 960 GB capacity per drive.​ Also note that, while the F210 is node pool compatible with the F200, a performance degradation is experienced where the F210 is effectively throttled to match the performance envelope of the F200s. ​

When an F210 is added to the F200 node pool, OneFS will display the following WebUI warning message alerting to this ‘soft restriction’:

And similarly from the CLI:

Hot on the heels of the recent OneFS 9.7 release sees the launch of two new PowerScale F-series hardware offerings. Between them, these new F710 and F210 all-flash nodes add some major horsepower to the PowerScale stable.

Built atop the latest generation of Dell’s PowerEdge R660 platform, the F710 and F210 each boast a range of Gen4 NVMe SSD capacities, paired with a Sapphire Rapids CPU, a generous helping of DDR5 memory, and PCI Gen5 100GbE front and back-end network connectivity – all housed within a compact, power-efficient 1RU form factor chassis.

Here’s where these new nodes sit in the current hardware hierarchy:

As illustrated in the greyed out region of the above chart, these new nodes refresh the current F600 and F200 platforms, and further extend PowerScale’s price-performance envelope.

The PowerScale F210 and F710 nodes offer a substantial hardware evolution from previous generations, while also focusing on environmental sustainability, reducing power consumption and carbon footprint. Housed in a 1RU ‘Smart Flow’ chassis for balanced airflow and enhanced cooling, both new platforms offer greater density than their F600 and F200 predecessors – the F710 now accommodating ten NVMe SSDs per node and 25% greater density, and the F210 now offering NVMe drives with a 15.36 TB option, and doubling the F200’s maximum density. Both platforms also include in-line compression and deduplication by default, further increasing their capacity headroom and effective density. Plus, using Intel’s 4^th gen Xeon Sapphire Rapids CPUs results in 19% lower cycles-per-instruction, while PCIe Gen 5 quadruples throughput over Gen 3, and the latest DDR5 DRAM offers greater speed and bandwidth – all netting up to 90% higher performance per watt. Additionally, the F710 and F210 debut a new 32 GB Software Defined Persistent Memory (SDPM) file system journal, in place of NVDIMM-n in prior platforms, thereby saving a DIMM slot on the motherboard too.

On the OneFS side, the recently launched 9.7 release delivers a dramatic performance bump – particularly for the all-flash platforms. OneFS 9.7 benefits from latency-improving enhancements to its locking infrastructure and protocol heads – plus ‘direct write’ non-cached IO, which we will explore in a future article.

This combination of generational hardware upgrades plus OneFS 9.7 software advancements results in dramatic performance gains for the F710 and F210 – particularly for streaming reads and writes, which see a 2x or greater improvement over the prior F600 and F200 platforms. This makes the F710 and F210 ideal candidates for demanding workloads such as M&E content creation and rendering, high concurrency and low latency workloads such as chip design (EDA), high frequency trading, and all phases of generative AI workflows, etc.

Scalability-wise, both platforms require a minimum of three nodes to form a cluster (or node pool), with up to a maximum of 252 nodes, and the basic specs for the new nodes include:

Component	PowerScale F710	PowerScale F210
CPU	Dual–socket Intel Sapphire Rapids, 2.6GHz, 24C	Single–socket Intel Sapphire Rapids, 2GHz, 12C
Memory	512GB DDR5 DRAM	128GB DDR5 DRAM
SSDs per node	10 x NVMe SSDs	4 x NVMe SSDs
Raw capacities per node	38.4TB to 307TB	7.7TB to 61TB
Drive options	3.84TB, 7.68TB TLC and 15.36TB, 30.72TB QLC	1.92TB, 3.84TB, 7.68TB TLC and 15.36TB QLC
Front-end network	2 x 100GbE or 25GbE	2 x 100GbE or 25GbE
Back-end network	2 x 100 GbE	2 x 100GbE or 25GbE

Note that, while the F210 can coexist with the F200 in the same node pool, the F710 does not currently have any node pool compatibility peers.

Over the next couple of articles, we’ll dig into the technical details of each of the new platforms. But, in summary, when combined with OneFS 9.7, the new PowerScale all-flash F710 and F210 platforms quite simply deliver on efficiency, flexibility, performance, and scalability.

In the first article in this series, we took a look at the overview and architecture of the OneFS 9.7 externally managed network pools feature. Now, we’ll turn our focus to its management and monitoring.

From a cluster security point of view, the externally managed IP service has opened up a potential new attack vector whereby a rogue DHCP server could provide bad data. As such, the recommendation is to configure a firewall around this new OneFS DHCP service to ensure that the cluster is protected. While the OneFS firewall could in theory provide this protection, in order to know what the DHCP server is, the cluster first has to discover and talk to the DHCP server and get its IP. This seems a bit paradoxical (and insecure) to be creating a firewall rule after having already talked to and trusted the DHCP server.

The following table contains recommended configuration settings for the AWS firewall.

Setting	Value
Name	Eg. ‘DHCP”
Type	‘ingress’
From Port	67
To Port	68
Protocol	UDP
CIDR Blocks	<cluster_gateway>/32
IPv6 CIDR Blocks	[]
Security Group ID	// customer specific

Note that, as mentioned in the first article in this series, there are a currently a couple of instances of unsupported networking functionality in the APEX file services for AWS offering, as compared to on-prem OneFS, and these include:

• IPv6 support
• VLANs
• Link aggregation
• NFSoverRDMA

These limitations for externally managed network pools are highlighted in red below, and are read-only settings since they are managed by the cloud provider (interfaces and IPs).

Externally managed network pools can only be created by the system with OneFS 9.7 and therefore pools cannot be manually reconfigured either to or from externally managed – even by root.

In general manual IP configuration is protected in order to guard against accidental misconfiguration. However, clusters admin may occasionally be required to manually configure the IPs in the network pool, and can be performed with the ‘isi network pool modify’ plus the inclusion of the ‘–force’ flag:

# isi network pool modify subnet0.pool0 –ranges <ip_add_range> --force

Note that AWS has a maximum threshold for the number of IPs that can be configured per network interface based on AMI instance type. If this limit is exceeded, AWS will prevent the IP address from being configured, resulting in a potential data unavailability event.  OneFS 9.7 now prevents most instances of IP oversubscription at configuration time in order to ensure availability during a 1/3 cluster outage.

While OneFS accounts for externally managed, static, dynamic IPs, and SSIPs, it is unable to account for unevenly allocated dynamic IPs, so it’s therefore unable to prevent all instances.

OneFS also displays an informative error message if attempting to configure this. For example, using an AMI instance type of ‘m5d.large’:

# isi network pool modify subnet0.pool0 –ranges 10.20.30.203-10.20.30.254

AWS only allows node 2 (instance type AWS=m5d.large) to have a maximum of 10 IPv4 addresses configured. In a degraded state, the requested configuration will result in node 2 attempting to configure 28 addresses, which will leave 18 address(es) unavailable. To resolve this, consider increasing the number of nodes in dynamic pools or reducing the number of IPv4 addresses.

When it comes to troubleshooting externally managed pools, there are two log files which are useful to check. Namely:

• /var/log/dhclient.log
• /var/log/isi_smartconnect

The first of these is a dedicated dhclient.log file for the new dhclient instance that OneFS 9.7 introduces. In contrast, the IP Merger and IP Reporter modules will output to the isi_smartconnect log.

There are also a handful of relevant system files that are also worth being aware of, and these include:

• /var/db/dhclient/lease.ena1
• /ifs/.ifsvar/modules/flexnet/ip_reporter/DHCP/node.
• /ifs/.ifsvar/modules/flexnet/pool_members/groupnet.1.subnet.1.pool.1
• /ifs/.ifsvar/modules/smartconnect/resource/workers/ip_merger

The first of these, lease.ena1, is an append log maintained by dhclient. So the most recent lease in there is the one that is SmartConnect is looking at. Note that there may be other lease files in the system, but only the lease files in /var/db/dhclient are relevant, and being viewed by SmartConnect. OneFS has a special configuration for dhclient to ensure this.

The IP reports live in the /ifs/.ifsvar/modules/flexnet directory. The pool_members directory has been present in OneFS for a number of years now. And OneFS now coordinates the IP merger with the file under ./smartconnect/resource/workers/ directory.

As for useful CLI commands, these include the following:

# isi_smartconnect_client action –a wake-ip-reporter

The ‘isi_smartconnect_client’ CLI utility, which can be used to interact with the SmartConnect daemon, gets an additional ‘wake-ip-reporter’ action in OneFS 9.7. Under normal circumstances, the IP Reporter only checks the contents of the lease file every five minutes. However, ‘wake-ip-reporter’ now instructs IP Reporter to check the lease file immediately. So if there was some issue where dhclient restarted for some reason, IP Reporter can be awoken and forced to read the lease, rather than waiting for its next scheduled check.

Additionally, the following ‘log_level’ command arguments can be used to change the logging level of SmartConnect to the desired verbosity:

# isi_smartconnect_client log_level [-l | -r]

Note that, in OneFS 9.7, this does not change the Flexnet config file which was required in prior releases.

Instead, this log level is reset when the process dies or the ‘–r’ argument is passed. It’s worth noting that this command does not operate cluster-wise. Rather, it just affects the current instance of SmartConnect running on the local node.

Another thing to be aware of when a cluster is using externally managed pools is that networking is dependent on, and can be impacted by, the availability of AWS’ DHCP servers. While the leased IP never changes, the leases themselves have an expiration of an hour. As such, if OneFS is unable to reach the DHCP server to renew, it may lose its Primary IPs. While this is often outside the realm of control, the OneFS CELOG event service will fire a critical warning alert (SW_SC_DHCP_LEASE_REBIND) before a primary IP expires. This alert will contain the following event description:

DHCP server has not responded to requests to renew lease on <interface>. Attempting to contact other DHCP servers. If we are unable to renew the lease, the IP address <ip_address> will be removed at expiry.

For example:

In addition to the above alert, there are several log messages that give a good indication of what may be amiss. These, and their resolution info, are summarized in the following table:

Log Message	Description	Resolution
Unable to merge IP 1.2.3.4 on ext-1 from devid 1 – no matching pool found	IP is not configured in any Network Pool	Add IP to the Primary IP Pool
Unable to parse lease on NIC: ena1. Attempting to retrieve new lease	The lease file generated by dhclient could not be read.	None should be required. We will automatically backup the old lease file and restart dhclient
Lease on NIC: ena1 not found	Lease file does not exist for the specified interface	OneFS will automatically restart dhclient
Unexpected error comparing IP Reports. Attempting rewrite	We try to dedupe writes by comparing newly generated IP report with what is on disk. In the event of a failure, we’ll just overwrite.
No IP Report received from DHCP External Manager	OneFS unable to determine its IP from the DHCP leases. Will continue retrying, but currently unable to report an IP	If issues persists, check on dhclient to ensure it is operating correctly.
Failed to write IP Report node. for DHCP to disk:	OneFS unable to report its IP to /ifs, so the IP merger is unable to update Flexnet/IP Assignments with this information.	Check why SmartConnect is unable to write to /ifs. Is it read only?

 

Tucked amongst the array of new functionality within OneFS 9.7’s payload is the debut of a networking feature called externally managed network pools. In layman’s terms, this is essentially the introduction of a front-end dynamic host control protocol (DHCP) client for the PowerScale cluster.

The context and motivation behind implementing this new functionality is predicated on the fact that cloud networking differs substantially from on-prem infrastructure. This is largely because the cloud hyperscalers typically require a primary IP to be configured on a specific interface that they dictate. Normally, systems operating within an off-prem environment obtain their network configuration via the DHCP protocol. But as you’re likely aware, until OneFS 9.7, DHCP has not been supported on a cluster’s front end network previously. To support APEX file services for AWS, OneFS 9.6 implemented a manual work-around for this, which had its limitations. However, with OneFS 9.7, the desire was to make the system smarter and by adding proper support for IPv4 primary IP addresses on AWS deployments, thereby negating the need for configuring manual work-arounds, with their inherent risks.

This new externally managed IP addresses feature is automatically enabled upon committing and upgrade to OneFS 9.7. To support this feature, a new network allocation method has been added to OneFS’ network pools called ‘externally managed’. This is actually managed by an external service such as AWS, which dictates where these primary IPs live. So they are in charge of IP allocation, rather than the cluster’s Flexnet or SmartConnect services, which has been the case up to now. It’s worth noting that OneFS 9.7 only includes (and enforces) limited DHCP support, strictly for cloud deployments currently. That said, on-prem DHCP support may be added in a future release but this is currently not on the near-term roadmap. Additional work was also included in OneFS 9.7 to prevent IP oversubscription.

So let’s take a look under the hood… Architecturally, there are three main components to the externally managed IP addresses feature:

• DHCP Service
• IP Reporter Module
• IP Merger Module

OneFS 9.7 actually talks DHCP by leveraging the FreeBSD ‘dhclient’ implementation. Dhclient is modified so it does not actually configure the network interfaces like it would normally, in order to avoid conflicts with the OneFS Flexnet network config daemon. Instead, dhclient just persists the leases to the following files:

• /ifs/.ifsvar/modules/flexnet/flx_config.xml

• /ifs/.ifsvar/modules/flexnet/pool_members/groupnet.1.subnet.1.pool.1.

Additionally, SmartConnect sees the addition of two new modules, IP Reporter and IP Merger.

Component	Details
DHCP service	Adds new MCP-controlled DHCP service: dhclient-ext-1 – Uses modified FreeBSD dhclient implementation – Does not configure network interfaces – Persists leases to /var/db/dhclient/
IP Merger	Adds new cluster-wide module to SmartConnect, IP Merger: – Coordinates ownership of the role by taking locks on files on /ifs – Loads all files from IP Reports directory – Verifies network pool is configured correctly and generates IP Assignments – Updates the following files: ▪ /ifs/.ifsvar/modules/flexnet/flx_config.xml ▪ /ifs/.ifsvar/modules/flexnet/pool_members/groupnet.1.subnet.1.pool.1
IP Reporter	Adds new module to each node’s SmartConnect service: – Parses DHCP leases – Converts to a generic format – Saves to /ifs/.ifsvar/modules/flexnet/ip_reports/DHCP/node.

These modules are still part of the overarching isi_smartconnect_d, and just new components within that same daemon. The IP Reporter module will parse the above lease files and then save the information to /ifs/.ifsvar/modules/flexnet/ip_reports/DHCP/node.

In contrast, the IP Merger is a single cluster-wide instance that loads the files from the IP Reports directory, verifies the network pool configuration, generates the IP assignments, and updates the config files. The ip_merger file contains the devID of the node that has been elected as responsible for IP merging. The full path is as follows:

/ifs/.ifsvar/modules/smartconnect/resource/workers/ip_merger

The following CLI syntax can be used to determine which node is acting as the merger: For example:

# isi_for_array 'grep "Taking ownership of the IPMerger role" /var/log/isi_smartconnect’

TME-4:  2024-02-07T16:26:20.946863+00:00 <3.6> GLaDOS-4(id4) isi_smartconnect_d[3626]: Taking ownership of the IPMerger role

In this case, the command output indicates that node ID4 has taken ownership of the IPMerger role.

The underlying process is very similar to how OneFS manages SSIPs in that all nodes attempt to lock a file under /ifs, and one granted that lock, they own that responsibility.  So OneFS takes the files from under /ifs/.ifsvar/modules/flexnet/ip_reports and merges the IP information into the Flexnet config and the pool members file, as follows:

The above graphic illustrates how data flows through the system from the cloud provider’s DHCP server, to dhclient, and then into isi_smartconnect_d. The modular, extensible architecture requires only a small portion of OneFS to be made aware of this new type of network pool. This all happens on the side until the data is merged into the Flexnet config and the associated state files, so it is low risk to everything else.

In OneFS 9.7, this new DHCP allocation method is now set as ‘externally managed’  for subnet0.pool0. This can be seen even on network pools that have been upgraded from an earlier OneFS release. Additionally, the CLI output also reports the type of external manager for this network pool – for instance AWS in the example below:

The ‘isi network interfaces’ CLI syntax is also updated in OneFS 9.7 to allow filtering by ‘externally managed’ pools. For example below, again showing that the owner is AWS:

As a quick reminder, there are a currently a couple of instances of unsupported networking functionality in the APEX file services for AWS offering, as compared to on-prem OneFS, and these include:

• IPv6 support
• VLANs
• Link aggregation
• NFSoverRDMA

In the next article in this  series we’ll turn our attention to the management, monitoring, and security of OneFS 9.7 externally managed network pools.

As we saw in the previous blog in this series, with the inclusion of Google Cloud (GCP) in OneFS 9.7, SmartSync Cloud Copy now supports all three of the principal public cloud hyperscalers.

Object data replication to Google Cloud (GCP) can be configured in OneFS 9.7 via the ‘isi dm accounts create’ CLI command. Required information includes the regular account configuration parameters plus the following GCP-specific settings:

• GCP account type
• GCP URI
• Access ID
• Secret key

Or, more specifically:

Parameter	Description
Object store type	GCP (or AWS_S3, Azure, ECS_S3, etc)
URI	{http,https}://hostname:port/bucketname
Auth	Access ID, Secret Key
Proxy	Optional proxy information

For example:

# isi dm account create --account-type GCP --name [Account Name] --access-id [GCP access-id] --uri [GCP URI with bucket-name] --auth-mode CLOUD --secret-key [GCP secret-key]

Once created, the new account can be verified with the following command:

# isi dm accounts list

Additionally, the next steps for SmartSync configuration and policy creation are covered in detail in the following blog article.

SmartSync Cloud Copy supports both push and pull replication, permitting the same dataset that is copied to GCP with a push to be copied back to the cluster via a corresponding pull.

Be aware that a dataset must be available before a policy runs, or the policy will fail.

Also note that, while multiple GCP URIs and credentials are supported by SmartSync, they are not supported on the same account. Multiple accounts and multiple corresponding policies would need to be created for SmartSync.

Other SmartSync features and functionality includes:

Feature	Details
Bandwidth throttling	Set of netmask rules. Limits are per-node.
CPU throttling	Allowed and Back-off CPU percentages.
Base policies	Template providing common values to groups of related policies (schedule, source base path, enable/disable, etc). Ie. Disabling base policy affects all linked concrete policies.
Concrete policy	Predefined set of fields from the base policy
Unconnected nodes (NANON)	Active accounts are monitored by each node. No work allocation to nodes without network access.
Snapshot locking	Avoids accidental snapshot deletion, with subsequent re-base-lining.

Behind the scenes, dataset creation leverages a SnapshotIQ snapshot, which can be inspected via the ‘isi snapshot list’ command. These DM dataset snapshots are easily recognizable due to their ‘isi_dm’ prefixed naming convention.

The SmartSync Cloud Copy format provides both regular file representation, browsability and usability of file system data in the cloud. In addition to the replication of the actual data, SmartSync also preserves the common file attributes including Windows ACLs, POSIX permissions and attributes, creation times, extended attributes, etc. However, there are certain considerations and limitations to be aware of, such as no incremental copy. These also include:

CloudCopy Caveats	Details
ADS files	Skipped when encountered.
Hardlinks	An object will be created for each link (ie. links are not preserved).
Symlinks	Skipped when encountered.
Directories	An object is created for each directory.
Special files	Skipped when encountered.
Metadata	Only POSIX mode bits, UID, GID, atime, mtime, ctime are preserved.
Filename encodings	Converted to UTF-8.
Path	Path relative to root copy directory is used as object key.
Large files	An error is returned for files larger than the cloud providers maximum object size.
Long filenames	File names exceeding 256 bytes are compressed.
Long paths	Junction points are created when paths exceed 1024 bytes to redirect where objects are being stored
Sparse files	Sparse sections are not preserved and are written out fully as zeros.

SmartSync allows subsequent incremental data movement by managing and re-transferring failed file transfers. Similarly, Dataset reconnect enables systems with common base datasets to establish instant incremental syncs. SmartSync also proactively locks the SnapshotIQ snapshots it uses, providing better separation between Datamover and other snapshots.

Performance-wise, SmartSync is powered by a scalable run-time engine, spanning the cluster, and which spins up threads (fibers) on demand and uses asynchronous IO to process replication tasks (chunks). Batch operations are used for efficient small file, attribute, and data block transfer. Namespace contention avoidance, efficient snapshot utilization, and separation of dataset creation from transfer are salient design features of the both the baseline and incremental sync algorithms.

Another feature addition that OneFS 9.7 delivers is support for Google Cloud (GCP) as a target for SmartSync, PowerScale’s next-gen data mover. With this enhancement, SmartSync Cloud Copy now supports all three of the principal public cloud hyperscalers – Amazon S3, Google Cloud Platform, and Microsoft Azure.

As you may be aware, this is not OneFS’ first foray into Google Cloud integration. CloudPools has supported GCP as a remote tiering target for several years now. Also, from the SmartSync perspective, while GCP represents a new account type, it fits within the existing cloud authentication mechanism, plus also uses an object protocol spec that’s based heavily on Amazon’s S3.

CloudCopy uses HTTP as the data replication transport layer to cloud storage, while traditional cluster to cluster SmartSync leverages a proprietary RCP-based messaging system.

In order to use SmartSync with GCP, the cluster must be running OneFS 9.7 and have SyncIQ licensed and active across all nodes in the cluster. Additionally, a cluster account with the ISI_PRIV_DATAMOVER privilege is needed in order to configure and run SmartSync data mover policies. While file-to-file replication requires SmartSync to be running on both source and target clusters, for OneFS Cloud Copy to transfer to/from cloud storage, only the cluster requires the SmartSync platform, and no data mover is required on the cloud systems. Be aware that the inbound TCP 7722 IP port must be open across any intermediate gateways and firewalls to allow SmartSync replication to occur.

Under the covers, replication is executed by the ‘isi_dm_d’ service, and the SmartSync data mover’s basic architecture is as follows:

The ‘isi_dm_d’ service is disabled by default and needs to be enabled prior to configuring and using SmartSync. SmartSync also uses TLS (transport layer security, or SSL) and, as such, requires trust to be established between the cluster and cloud target.

The SmartSync Datamover also includes a purpose-build, integrated scheduler and job control and execution framework, which operates along these lines:

Shared Key-Value Stores (KVS) are used for jobs/tasks distribution, and extra indexing is implemented for quick lookups by task state, task type, and alive time. There are no dependencies or communication between tasks, and job cancellation and pausing is handled by posting a ‘request’ into a job record (request polling).

Within the SmartSync hierarchy, accounts define the connections to remote systems, policies define the replication configurations, and jobs perform the work, or tasks:

Component	Details
Accounts	Datamover accounts: –          URI, eg. dm://remotenas.isln.com:7722 –          Network pools defining nodes/interfaces to use for data transfer –          Client and server certificates to enable TLS CloudCopy accounts: –          Account type (AWS S3, Azure, GCP, ECS S3) –          URI, eg. https://cloudcluster.isln.com:9002/cloudbucket –          Credentials
Policies	–          Dataset creation policy –          Dataset copy policy –          Dataset repeat copy policy –          Dataset expiration policy
Jobs	Runtime entities created based on policies schedules. There are two major types of data transfer jobs: –         Baseline jobs for initial transfers and –         Incremental jobs for subsequent transfers between FILE Datamover systems.
Tasks	Spawned by jobs and are the individual chunks of work that a job must perform. No 1-to-1 relationship to their associated files.

So, in order to configure SmartSync to use GCP as a cloud target, the following prerequisites are required:

Requirement	Detail
Account	GCP account and credentials to use with feature
License	SyncIQ license across the cluster
OneFS version	OneFS 9.7 or higher installed and committed for GCP..
Privileges	Cluster account with the ISI_PRIV_DATAMOVER role to configure & manage.

While SmartSync is automatically installed in OneFS 9.4 and later, it is inactive by default. As such, there is no impact from the feature unless it is enabled.

To verify that GCP support is available, the account type will be listed in the output of from the ‘isi dm account create –help’ CLI command.

For example,:

# uname -sr

Isilon OneFS 9.7.0.0

# isi dm account create --help | grep -i gcp

    <account-type> (DM | AWS_S3 | ECS_S3 | AZURE | GCP)

Currently, SmartSync configuration is limited to the CLI or platform API, with WebUI support planned for a future release. As such, configuration is typically performed via the ‘isi dm’ CLI utility, which contains the following the principal subcommands:

Subcommand	Description
isi dm accounts	Manage Datamover accounts. An activate SyncIQ license is required to create Datamover accounts.
isi dm base-policies	Manage Datamover base-policy. Base policies are templates to provide common values to groups of related concrete Datamover policies. Eg. Define a base policy to override the run schedule of a concrete policy.
isi dm certificates	Manage Datamover certificates.
isi dm config	Show Datamover Manual Configuration.
isi dm datasets	Show Datamover Dataset Information.
isi dm historical-jobs	Manage Datamover historical jobs.
isi dm jobs	Manage Datamover jobs.
isi dm policies	Manage Datamover policy. Policies can be either: CREATION – Creates/replicates a dataset, either once or on a schedule. COPY – Defines a one-time copy of a dataset to or from a remote system
isi dm throttling	Manage Datamover bandwidth and CPU throttling. Bandwidth throttling rules can be configured for each Datamover job.

In the next article in this series, we’ll look at the configuration required to use SmartSync with Google Cloud (GCP).

The previous article in this series took a look at the enhancements and supporting architectural changes to OneFS cluster configuration backup and restore in the OneFS 9.7 release. Now, we’ll focus on its operation and management.

By default, the cluster configuration backup and restore files reside at:

File	Location
Backup file	/ifs/data/Isilon_Support/config_mgr/backup/<JobID>/<component>_<JobID>.json
Restore file	/ifs/data/Isilon_Support/config_mgr/restore/<JobID>/<component>_<JobID>.json

The log file for configuration manager is located at /var/log/config_mgr.log and can be useful to monitor the progress of a config backup and restore, especially for any troubleshooting purposes.

So let’s take a look at this cluster configuration management process:

The following example steps through the export and import of a cluster’s NFS and SMB configuration – within the same cluster. This can be accomplished as follows:

1. First, create some SMB shares and NFS exports using the following CLI commands:

# isi smb shares create --create-path --name=test --path=/ifs/test

# isi smb shares create --create-path --name=test2 --path=/ifs/test2

# isi nfs exports create --paths=/ifs/test

# isi nfs exports create --paths=/ifs/test2

2. Next, export the NFS and SMB configuration using the following CLI command:

# isi cluster config exports create --components=nfs,smb --verbose
The following components' configuration are going to be exported:
['nfs', 'smb']
Notice:
    The exported configuration will be saved in plain text. It is recommended to encrypt it according to your specific requirements.
Do you want to continue? (yes/[no]): yes
This may take a few seconds, please wait a moment
Created export task ' PScale-20240118105345'

From the above, the job ID for this export task is ‘ PScale-20240118105345’.

As the warning indicates, the configuration backup is saved in plain text. However, sensitive information is not exported.

3. The results of the export operation can be verified with the following CLI command, using the job ID for this operation:

# isi cluster config exports view PScale-20240118105345
     ID: PScale-20240118105345
 Status: Successful
   Done: ['nfs', 'smb']
 Failed: []
Pending: []
Message:
   Path: /ifs/data/Isilon_Support/config_mgr/backup/PScale-20240118105345

4. The JSON files can be viewed under /ifs/data/Isilon_Support/config_mgr/backup/PScale-20240118105345.

# ls /ifs/data/Isilon_Support/config_mgr/backup/PScale-20240118105345
backup_readme.json             
nfs_PScale-20240118105345.json 
smb_PScale-20240118105345.json

Note that OneFS generates a separate configuration backup JSON file for each component (ie. SMB and NFS in this example), plus a readme file which provides a synopsis of the backup operation.

5. The SMB shares and NFS exports can be deleted as follows:

# isi smb shares delete test

# isi smb shares delete test2

# isi nfs exports delete 9

# isi nfs exports delete 10

6. The prior SMB and NFS configuration can now be easily restored with the following CLI syntax:

# isi cluster config imports create PScale-20240118105345 --components=nfs,smb --verbose
Source Cluster Information:
          Cluster name: PScale
       Cluster version: 9.7.0.0
            Node count: 4
  Restoring components: ['nfs', 'smb']
Notice:
    Please review above information and make sure the target cluster has the same hardware configuration as the source cluster, otherwise the restore may fail due to hardware incompatibility. Please DO NOT use or change the cluster while configurations are being restored. Concurrent modifications are not guaranteed to be retained and some data services may be affected.
Do you want to continue? (yes/[no]):
This may take a few seconds, please wait a moment
Created import task 'PScale-2024011810345'

7. To view the restore results, use the following command:

# isi cluster config imports view PScale-20240118105345
       ID: PScale-20240118110659
Export ID: PScale-20240118105345
   Status: Successful
     Done: ['nfs', 'smb']
   Failed: []
  Pending: []
  Message:
     Path: /ifs/data/Isilon_Support/config_mgr/restore/ PScale-20240118110659

8. Finally, verify that the SMB shares and NFS exports are restored:

# isi smb shares list
Share Name  Path
----------------------
test        /ifs/test
test2       /ifs/test2
----------------------
Total: 2

# isi nfs exports list
ID   Zone   Paths      Description
-----------------------------------
11   System /ifs/test
12   System /ifs/test2
-----------------------------------
Total: 2

Currently, cluster configuration backup and restore is only available via the CLI and platform API. However, a WebUI management component is planned for a future release, as is the ability to run a diff, or comparison, between two exported configurations.

One other significant enhancement to cluster configuration backup and restore is the support for custom network rules for restoring subnet IP addresses, allowing cluster admins to assign different IP address from backup for restoring a new subnet. This ensures that a network restore will not overwrite any existing subnets and pools’ IP addresses on the target cluster, thereby avoid connectivity breaks. The CLI syntax for specifying cluster configuration restore custom network rules is as follows:

# isi cluster config imports create \ --components network \ --network-subnets-ip <string>

For example, the following CLI syntax will configure the target cluster’s groupnet0.subnet1 network to use 10.1.10.0 and a netmask of 255.255.255.252 and its groupnet1.subnet0 to use 10.2.20.0 with a netmask of 255.255.255.0:

# isi cluster config imports create \ --components network \ --network-subnets-ip "groupnet0.subnet1:10.1.10.0/22,groupnet1.subnet0:10.2.20.0/24"

When it comes to troubleshooting the cluster config backup and restore, the first place to check is the output of the ‘isi cluster config exports|imports view’ CLI commands. The backups themselves can be found under /ifs/data/Isilon_Support/config_mgr/backup/. After this, the next place to look for information is the log file, located at /var/log/config_mgr.log. Additionally, the job database, which resides at /ifs/.ifsvar/modules/config_mgr/config.sqlite, can also be queried in a pinch. However, exercise caution since this job DB should not be modified under any circumstances.

The basic ability to export a cluster’s configuration, which can then be used to perform a config restore, has been available since OneFS 9.2. However, OneFS 9.7 sees an evolution of the cluster configuration backup and restore architecture plus a significant expansion in the breadth of supported OneFS components, which now includes authentication, networking, multi-tenancy, replication, and tiering:

A configuration export and import can be performed via either the OneFS CLI or platform API, and encompasses the following OneFS components for configuration backup and restore:

Component	Configuration / Action	Release
Auth	Roles:          Backup / Restore Users:          Backup / Restore Groups:       Backup / Restore	OneFS 9.7
Filepool	Default-policy:       Backup / Restore Policies:       Backup / Restore	OneFS 9.7
HTTP	Settings:       Backup / Restore	OneFS 9.2+
NDMP	Users:       Backup / Restore Settings:       Backup / Restore	OneFS 9.2+
Network	Groupnets:       Backup / Restore Subnets:       Backup / Restore Pools:       Backup / Restore Rules:       Backup / Restore DNScache:       Backup / Restore External:       Backup / Restore	OneFS 9.7
NFS	Exports:       Backup / Restore Aliases:       Backup / Restore Netgroup:       Backup / Restore Settings:       Backup / Restore	OneFS 9.2+
Quotas	Quotas:       Backup / Restore Quota notifications:       Backup / Restore Settings:       Backup / Restore	OneFS 9.2+
S3	Buckets:       Backup / Restore Settings:       Backup / Restore	OneFS 9.2+
SmartPools	Nodepools:       Backup Tiers:       Backup Settings:       Backup / Restore	OneFS 9.7
SMB	Shares:       Backup / Restore Settings:       Backup / Restore	OneFS 9.2+
Snapshots	Schedules:       Backup / Restore Settings:       Backup / Restore	OneFS 9.2+
SmartSync	Accounts:       Backup / Restore Certificates:       Backup Base-policies:       Backup / Restore Policies:       Backup / Restore Throttling:       Backup / Restore	OneFS 9.7
SyncIQ	Policies:       Backup / Restore Certificates:       Backup Rules:       Backup Settings:       Backup / Restore	OneFS 9.7
Zone	Zones:       Backup / Restore	OneFS 9.7

 

In addition to the above expanded components support,  the principal feature enhancements added to cluster configuration backup and restore in OneFS 9.7 include:

• Addition of a daemon to manage backup/restore jobs.
• The ability to lock the configuration during a backup.
• Support for custom rules when restoring subnet IP addresses.

Let’s first take a look at the overall architecture. The legacy cluster configuration backup and restore infrastructure in OneFS 9.6 and earlier was as follows:

By way of contrast, OneFS 9.7 now sees the addition of a new configuration manager daemon, adding a fifth layer to the stack, and also increasing security and guarantying configuration consistency/idempotency:

The various layers in this OneFS 9.7 architecture can be characterized as follows:

Architectural Layer	Description
User Interface	Allows users to submit operations with multiple choices, such as PlatformAPI or CLI.
pAPI Handler	Performs different actions according to the requests flowing in.
Config Manager Daemon	New daemon in OneFS 9.7 to manage backup and restore jobs.
Config Manager	Core layer executing different jobs which are called by PAPI handlers.
Database	Lightweight database manage asynchronous jobs, tracing state and receiving task data.

 

The new configuration management (ConfigMgr) daemon receives job requests from the platform API export and import handlers, and launches the corresponding backup and restore jobs as required. The backup and restore jobs will call a specific component’s pAPI handler in order to export of import the configuration data. Exported configuration data itself is saved under /ifs/data/Isilon_Support/config_mgr/backup/, while the job information and context is saved to a SQLite job information database that resides at /ifs/.ifsvar/modules/config_mgr/config.sqlite.

Enabled by default, the ConfigMgr daemon runs as a OneFS service, and can be viewed and managed as such:

# isi services -a | grep -i config_mgr

   isi_config_mgr_d     Config mgr Daemon                        Enabled

This isi_config_mgr_d daemon is managed by MCP, OneFS’ main utility for distributed service control across a cluster.

MCP is responsible for starting, monitoring, and restarting failed services on a cluster. It also monitors configuration files and acts upon configuration changes, propagating local file changes to the rest of the cluster. MCP is actually comprised of three different processes, one for each of its modes:

The ‘Master’ is the central MCP process and does the bulk of the work. It monitors files and services, including the failsafe process, and delegates actions to the forker process.

The role of the ‘Forker’ is to receive command-line actions from the master, execute them, and return the resulting exit codes. It receives actions from the master process over a UNIX domain socket. If the forker is inadvertently or intentionally killed, it’s automatically restarted by the master process. If necessary, MCP will continue trying to restart the forker at an increasing interval. If, after around ten minutes of unsuccessfully attempting to restart the forker, MCP will fire off a CELOG alert, and continue trying. A second alert would then be sent after thirty minutes.

MCP ensures the correct state of the service on a node, and since isi_config_mrg_d is marked ‘enable’ by default, it will run the start action until the PID confirms the daemon is running. MCP monitors services by observing their PID files (under /var/run), plus the process table itself, to determine if a process is already running or not, comparing this state against the ‘enabled/disabled’ configuration for the service and determining whether any start or stop actions are required.

In the event of an abnormal termination of a configuration restore job, the job status will be updated in the job info database, and MPC will attempt to restart the daemon. But if a configuration backup job fails, the daemon will assist in freeing the configuration lock, too. While the backup job is running, it will lock the configuration to prevent changes until the backup is complete, guarding against any potential race-induced inconsistencies in the configuration data.  Typically the config backup job execution is swift, so the locking effect on the cluster is minimal. Also, config locking does not impact in-progress POST, PUT, DETELE changes. Once successfully completed, the backup job will automatically relinquish its configuration lock(s). Additionally, the ‘isi cluster config lock’ CLI command set can be used to both view state and manually modify (enable or disable) the configuration locks.

The other main enhancement to configuration backup and restore in OneFS 9.7 is the ability to create custom rules for restoring subnet IP addresses. This allows the assignment of different IP address from the backup when restoring the network config on a target cluster. As such, a network configuration restore will not attempt to overwrite any existing subnets and pools’ IP addresses, thus avoiding a potential connectivity disruption.

In the next article in this series we’ll take a look at the operation and management of cluster configuration backup and restore.

In the final article in this series, we take a look at the configuration and management of parallel restriping. To support this, OneFS 9.7 includes a new ‘isi job settings’ CLI command set, allowing the parallel restriper configuration to be viewed and modified. By default, no changes are made to the Job Engine upon upgrade to 9.7, so the legacy behavior allowing only a single restripe job to run at any point in time is preserved. This is reflected in the new ‘isi job settings’ CLI syntax:

# isi job settings view

Parallel Restriper Mode: Off

However, once a OneFS 9.7 upgrade has been committed, the parallel restriper can be configured in one of three modes:

Mode	Description
Off	Default: Legacy restripe exclusion set behavior, with only one restripe job permitted.
Partial	FlexProtect/FlexProtectLin runs alone, but all other restripers can be run together.
All	No restripe job exclusions, beyond the overall limit of three concurrently running jobs.

For example, the following CLI command can be used to configure ‘partial’ parallel restriping support:

# isi job settings modify --parallel_restriper_mode=partial

# isi job settings view

Parallel Restriper Mode: Partial

As such, restriping jobs can run in parallel in ‘partial’ mode. For example, SmartPools and MultiScan, as in the following cluster‘s CLI output:

# isi job jobs list

ID   Type       State   Impact  Policy  Pri  Phase  Running Time

-----------------------------------------------------------------

3166 MultiScan  Running Low     LOW     4    1/4    17d 8h 5m

3790 SmartPools Running Low     LOW     6    1/2    5d 17h 16m

-----------------------------------------------------------------

Total: 2

However, if the FlexProtect is started when a cluster is in ‘partial’ mode, all other restriping jobs are automatically paused. For example:

# isi job jobs start FlexProtect

Started job [4088]

# isi job jobs start FlexProtect

Started job [4114]

# isi job jobs list

ID   Type        State              Impact  Policy  Pri  Phase  Running Time

-----------------------------------------------------------------------------

3790 SmartPools  Waiting            Low     LOW     6    1/2    36s

3166 MultiScan   Running -> Waiting Low     LOW     4    1/4    28s

4114 FlexProtect Waiting            Medium  MEDIUM  1    1/6    -

-----------------------------------------------------------------------------

Total: 3

# isi job jobs list

ID   Type        State   Impact  Policy  Pri  Phase  Running Time

------------------------------------------------------------------

3166 MultiScan   Waiting Low     LOW     4    1/4    17d 8h 7m

3790 SmartPools  Waiting Low     LOW     6    1/2    5d 17h 17m

4088 FlexProtect Running Medium  MEDIUM  1    1/6    2s

------------------------------------------------------------------

Total: 3

Similarly, no restripe job exclusions can be implemented with the following CLI syntax:

# isi job settings modify --parallel_restriper_mode=all

This allows any of the restriping jobs, including FlexProtect, to run in parallel up to the Job Engine limit of three concurrent jobs. For example, MultiScan and SmartPools are both running below:

# isi job jobs list

ID   Type       State   Impact  Policy  Pri  Phase  Running Time

-----------------------------------------------------------------

3166 MultiScan  Waiting Low     LOW     4    1/4    17d 8h 7m

3790 SmartPools Waiting Low     LOW     6    1/2    5d 17h 17m

-----------------------------------------------------------------

Total: 2

# isi job settings view

Parallel Restriper Mode: All

If the FlexProtect job is then started, all three restriping jobs are allowed to run concurrently:

# isi job jobs start FlexProtect

Started job [4089]

# isi job jobs list

ID   Type        State   Impact  Policy  Pri  Phase  Running Time

------------------------------------------------------------------

3166 MultiScan   Running Low     LOW     4    1/4    17d 8h 8m

3790 SmartPools  Running Low     LOW     6    1/2    5d 17h 18m

4089 FlexProtect Running Medium  MEDIUM  1    1/6    3s

------------------------------------------------------------------

Total: 3

Furthermore, the restripe jobs, including FlexProtect, can be run with the desired priority and impact settings. For example:

# isi job jobs start Flexprotect --policy LOW --priority 6

Started job [4100]

# isi job jobs list

ID   Type        State   Impact  Policy  Pri  Phase  Running Time

------------------------------------------------------------------

4097 SmartPools  Running Medium  MEDIUM  1    1/2    1m 42s

4098 MultiScan   Running Medium  MEDIUM  1    1/4    1m 13s

4100 FlexProtect Running Low     LOW     6    1/6    -

------------------------------------------------------------------

Total: 3

If necessary, the Job Engine can always be easily reverted to its default restripe exclusion set behavior, with only one restripe job permitted, as follows:

 # isi job settings modify --parallel_restriper_mode=off

Note that a user account with the PRIV_JOB_ENGINE RBAC role is required to configure the parallel restripe settings.

Similar to other Job Engine configuration, the parallel restripe settings are stored in gconfig under the core.parallel_restripe_mode tree.

Like any multi-threaded or parallel architecture, contending restriping jobs may lock LINs for long periods due to bigger range locks. Also, since by nature restriping jobs are moving blocks around, they tend to be quite hard on drives. So, multiple restripers running in parallel have the potential to impact cluster performance and potentially client I/O (protocol throughput, etc) – especially if the contending restripe jobs are run at a MEDIUM impact.

Also note that the new parallel restripe mode only applies to waiting jobs, or jobs transitioning between phases. Typically, if you attempt to start a second job with restripe exclusion enabled, that second job will be placed into a ‘waiting’ state. If parallel restripe is then enabled, the second job will be re-evaluated, and promoted to a ‘running’ state. However, if both jobs are running and parallel restripe is then disabled, the second job will not automatically be paused. Instead, intervention from a cluster admin would be needed to manually pause that job, if desired.

Note too that restripe exclusion is on a per-job-phase basis. For example, the MultiScan job has four phases. The first three can restripe, while the fourth does not. As such, a different restriping job (e.g. SmartPools or FlexProtect) will not conflict with MultiScan’s fourth phase. There’s also no need to run AutoBalance and a restriping MultiScan at the same time since they do exactly the same thing.
Additionally, unless there’s a really valid reason to, a good practice is to avoid running AutoBalance or MultiScan while FlexProtect is running. Re-protecting the cluster is usually of considerably more importance than correct balance, so allowing FlexProtect to consume any available resources while it’s running is typically a prudent move.

When troubleshooting the parallel restriper, the Job Engine coordinator logs to both isi_job_d.log and /var/log/messages, writing both the initial value and the subsequent configuration change. This can be a good thing to check if unexpectedly high drive load is encountered. Maybe someone inadvertently enabled parallel restripe, or at least forgot to disable it again after an intended short term configuration change.

One of the issues is that, in trying to keep the cluster healthy, jobs such as FlexProtect, MultiScan, and AutoBalance are run, often in degraded conditions. And these maintenance jobs are conflicting with customer assigned jobs like SmartPools, in particular.

In order to run restripe jobs in parallel, the Job Engine makes use of multi-writer. Within the OneFS locking hierarchy, multi-writer allows a cluster to support concurrent writes to the same file from multiple writer threads. This granular write locking is achieved by sub-diving the file into separate regions and granting exclusive data write locks to these individual ranges, as opposed to the entire file. This process allows multiple clients, or write threads, attached to a node to simultaneously write to different regions of the same file.

Concurrent writes to a single file need more than just supporting data locks for ranges. Each writer also needs to update a file’s metadata attributes such as timestamps, block count, etc.

A mechanism for managing inode consistency is also needed, since OneFS is based on the concept of a single inode lock per file.

In addition to the standard shared read and exclusive write locks, OneFS also provides the following locking primitives, via journal deltas, to allow multiple threads to simultaneously read or write a file’s metadata attributes:

Lock Type	Description
Exclusive	A thread can read or modify any field in the inode. When the transaction is committed, the entire inode block is written to disk, along with any extended attribute blocks.
Shared	A thread can read, but not modify, any inode field.
DeltaWrite	A thread can modify any inode fields which support deltawrites. These operations are sent to the journal as a set of deltas when the transaction is committed.
DeltaRead	A thread can read any field which cannot be modified by inode deltas.

These locks allow separate threads to have a Shared lock on the same LIN, or for different threads to have a DeltaWrite lock on the same LIN. However, it is not possible for one thread to have a Shared lock and another to have a DeltaWrite. This is because the Shared thread cannot perform a coherent read of a field which is in the process of being modified by the DeltaWrite thread.
The DeltaRead lock is compatible with both the Shared and DeltaWrite lock. Typically the filesystem will attempt to take a DeltaRead lock for a read operation, and a DeltaWrite lock for a write, since this allows maximum concurrency as all these locks are compatible.

Here’s what the write lock compatibilities looks like:

OneFS protects data by writing file blocks (restriping) across multiple drives on different nodes. The Job Engine defines a ‘restripe set’ comprising jobs which involve file system management, protection and on-disk layout. The restripe set contains the following jobs:

• AutoBalance & AutoBalanceLin
• FlexProtect & FlexProtectLin
• FilePolicy
• MediaScan
• MultiScan
• SetProtectPlus
• SmartPools
• Upgrade

Note that OneFS multi-writer ranges are not a fixed size and instead tied to layout/protection groups. So typically in the megabytes size range.

The number of threads that can write to the same file concurrently, from the filesystem perspective, is only limited by file size. However, NFS file handle affinity (FHA) comes into play from the protocol side, and so the default is typically eight threads per node.

The clients themselves do not apply for granular write range locks in OneFS, since multi-writer operation is completely invisible to the protocol. Multi-writer uses proprietary locking which OneFS performs to coordinate filesystem operations. As such, multi-writer is distinct from byte-range locking that application code would call, or even oplocks/leases which the client protocol stack would call.

Depending on the workload, multi-writer can improve performance by allowing for more concurrency. Unnecessary contention should be avoided as a general rule. For example:

• Avoid placing unrelated data in the same directory. Use multiple directories instead. Even if it is related, split it up if there are many entries.
• Similarly, use multiple files. Even if the data is ultimately related, from a performance/scalability perspective, having each client use its own file and then combining them as a final stage is the correct way to architect for performance.

Multi-writer for restripe, introduced in OneFS 8.0, allows multiple restripe worker threads to operate on a single file concurrently. This in turn improves read/write performance during file re-protection operations, plus helps reduce the window of risk (MTTDL) during drive Smartfails, etc. This is particularly true for workflows consisting of large files, while one of the above restripe jobs is running. Typically, the larger the files on the cluster, the more benefit multi-writer for restripe will offer.

With multi-writer for restripe, an exclusive lock is no longer required on the LIN during the actual restripe of data. Instead, OneFS tries to use a delta write lock to update the cursors used to track which parts of the file need restriping. This means that a client application or program should be able to continue to write to the file while the restripe operation is underway. An exclusive lock is only required for a very short period of time while a file is set up to be restriped.  A file will have fixed widths for each restripe lock, and the number of range locks will depend on the quantity of threads and nodes which are actively restriping a single file.

Prior to the multi-writer feature work, back in Riptide/OneFS 8.0, it was unsafe to run multiple restripe jobs – plain and simple. Since then, it is possible for these jobs to contend. However, these are often the ones that customers complain about the performance of. So an abundance of caution was exercised, and field feedback gathered, before engineering made the decision to allow parallel restriping.

On committing a OneFS 9.7 upgrade, the default mode is to change nothing and retain the restriping exclusion set and its single job restriction. However, a new CLI configuration option is now provided, allowing a cluster admin with the PRIV_JOB_ENGINE RBAC role to enable parallel restripe, if so desired.

There is no WebUI option to configure parallel restripe at this point – just CLI and platform API for now.

Most of the restriping jobs impact the cluster more heavily than desirable. So, depending on how loaded the cluster is, it was prudent to continue with the exclusion set as default, and allow the customer to make changes appropriate to their environment.