IBM Support

V8.3.1.x Configuration Limits and Restrictions for IBM System Storage SAN Volume Controller

Preventive Service Planning


Abstract

This document lists the configuration limits and restrictions specific to SAN Volume Controller software version 8.3.1.x

Content

V8.3.x does not support CG8 or earlier node types. Only DH8 or later nodes can be upgraded to v8.3.x.

The use of WAN optimisation devices such as Riverbed is not supported in native Ethernet IP partnership configurations containing SAN Volume Controller.


Data Reduction Pools

The following restrictions apply for Data Reduction Pools (DRP):

  1. Child pools are not supported in a DRP;
  2. VVOL is not supported in a DRP (because child pool is not supported);
  3. A volume in a DRP cannot be shrunk;
  4. No volume move between I/O groups if volume in a DRP (use FlashCopy or Metro Mirror/Global Mirror instead);
  5. No split of a volume mirror to copy in a different I/O group;
  6. Real/used/free/free/tier capacity are not reported per volume - only per pool.

Note: These restrictions are applicable to all the versions of IBM Spectrum Virtualize v8.1.2 and later


REST API

Customers using the REST API to list more than 2000 objects may experience a loss of service, from the API, as it restarts due to memory constraints.

It is not possible to access the REST API using a cluster's IPv6 address.


NVMe over Fibre Chanel
Hosts using the NVMe protocol cannot be mapped to HyperSwap or stretched volumes.
Volumes accessed by hosts using the NVMe protocol cannot be configured with multiple access I/O groups due to a limitation of the NVMe protocol.


DRAID Strip Size
For candidate drives, with a capacity greater than 4TB, a strip size of 128 cannot be specified for either RAID-5 or RAID-6 DRAID arrays. For these drives a strip size of 256 should be used.


Hot Spare Node
In a situation where an adapter PCI slot location on the spare node does not match the active nodes, an active node cannot be replaced by a spare node using the swapnode command. The user will encounter error "CMMVC9261E The command failed because the specified node does not have a status of candidate". It is recommended to have adapters in the same slot for spare nodes and the active node for swapnode replace command to work.

When the online_spare node is put into the Service state, it is immediately removed back to spare and 5 minutes later it will rejoin as online_spare in the cluster. The user can, instead of putting the online_spare into service, wait for the original to come back or simply remove the online_spare and then perform their maintenance.


Transparent Cloud Tiering

Transparent cloud tiering on the system is defined by configuration limitations and rules. Please see the Knowledge Center maximum limits page for details.

The following restrictions apply for Transparent Cloud Tiering:

  1. When a cloud account is created, it must continue to use the same encryption type, throughout the life of the data in that cloud account - even if the cloud account object is removed and remade on the system, the encryption type for that cloud account may not be changed while back up data for that system exists in the cloud provider.
  2. When performing re-key operations on a system that has an encryption enabled cloud account, perform the commit operation immediately after the prepare operation. Remember to retain the previous system master key (on USB or in Keyserver) as this key may still be needed to retrieve your cloud backup data when performing a T4 recovery or an import.
  3. Restore_uid option should not be used when backup is imported to a new cluster.
  4. Import of TCT data is only supported from systems whose backup data was created at v7.8.0.1 or later.
  5. Transparent cloud tiering uses Sig V2, when connecting to Amazon regions, and does not currently support regions that require Sig V4.

Encryption and TCT

There is an extremely small possibility that, on a system using both Encryption and Transparent Cloud Tiering, the system can enter a state where an encryption re-key operation is stuck in 'prepared' or 'prepare_failed' state, and a cloud account is stuck in 'offline' state.
The user will be unable to cancel or commit the encryption rekey, because the cloud account is offline. The user will be unable to remove the cloud account because an encryption rekey is in progress.
The system can only be recovered from this state using a T4 Recovery procedure.
It is also possible that SAS-attached storage arrays go offline.
There are two possible scenarios where this can happen:

Scenario A

  1. Using USB encryption and Cloud;
  2. A new USB key is prepared using chencryption -usb newkey -key prepare;
  3. The new presumptive key is deleted from all USB sticks before the new key is committed;
  4. All nodes in the system are rebooted;
  5. The cloud account will now be offline as it can't get the presumptive key. The cloud account can not be removed, and the encryption rekey can not be completed or cancelled. The system will remain stuck in these cloud and encryption states;
  6. Any SAS-attached arrays will be offline and locked;
  7. The system can be restored by T4 to a previous config backup.

Scenario B

  1. Using key server encryption and Cloud;
  2. A new key server key is prepared using chencryption -keyserver newkey -key prepare;
  3. The new presumptive key is deleted from the key server before the new key is committed;
  4. All nodes in the system are rebooted;
  5. The cloud account will now be offline as it can't get the presumptive key. The cloud account can not be removed, and the encryption rekey can not be completed or cancelled. The system will remain stuck in these cloud and encryption states;
  6. SAS-attached arrays are not affected;
  7. The system can be restored by T4 to a previous config backup.


NPIV ( N_Port ID Virtualization )

The following recommendations and restrictions should be followed when implementing the NPIV feature.

FCoE is not supported with NPIV.

Operating systems not currently supported for use with NPIV:
RHEL6 and earlier on IBM Power
HPUX 11iV2
Veritas DMP multipathing on Windows with RAID-5 volumes in VxVM

General requirements

Required SDD versions for IBM AIX and Microsoft Windows Environments:

  1. IBM AIX Operating Systems require a minimum SDDPCM version of 2.6.8.0 or AIXPCM;
  2. Microsoft Windows requires a minimum SDDDSM version 2.4.7.0. The latest recommended level which resolves issues listed below is 2.4.7.1.

Path Optimisation

User intervention may be required when changing NPIV states from "Transitional" to "Disabled". All Paths to a LUN with SDDDSM or SDDPCM may remain "Non-Optimized" when NPIV is "Disabled" from "Transitional" state. 
To resolve this issue please use the following instructions:

IBM AIX 
For SDDPCM: 
Run "pcmpath chgprefercntl device <device number>/<device number range>" on AIX. This will restore both Optimized and Non-Optimized paths for all the LUNs correctly. 

Windows 2008 and 2012 
For SDDDSM: 
Run "datapath rescanhw" on Windows. This will restore both Optimized and Non-Optimized paths for all the LUNs correctly. 
This issue is resolved with SDDDSM version 2.4.7.1 
    
Windows 2008 and 2012 Non-Preferred Paths with SDDDSM 
When NPIV enters into Transitional state from Disabled, with all the SDDDSM paths in Non-Preferred state, the paths to the Virtual ports also become Non-Preferred. This path configuration might cause IO failures as soon as NPIV moves into "Enabled" state. 
As a work around user should configure "at least one preferred path" to each LUN, when in NPIV "Disabled" state. 
This issue is resolved with SDDDSM version 2.4.7.1 

Solaris 
Emulex HBA Settings:
1. When implementing NPIV on Solaris 11 the default disk IO timeout needs to be changed to 120s by adding "set sd:sd_io_time=120" in /etc/system file, A system reboot is required for the change to be implemented. 
2. When ports on host HBA are connected to 16GB SAN, NPIV is not supported.

Other Operating Systems
Other operating Systems may also experience the same issue when changing the NPIV state from "Transitional" to "Disabled" in which case the operating system specific rescan command should be used. 

Fabric Attachment
NPIV mode on SVC or Storwize is only supported when used with Brocade or Cisco fibre channel SAN switches which are NPIV capable.


Nodes in an IO group cannot be replaced by nodes with less memory when compressed volumes are present

If a customer must migrate from 64GB to 32GB memory node canisters in an IO group, they will have to remove all compressed volume copies in that IO group.

A customer must not:

  1. Create an IO group with node canisters with 64GB of memory.
  2. Create compressed volumes in that IO group.
  3. Delete both node canisters from the system with CLI or GUI.
  4. Install new node canisters with 32GB of memory and add them to the configuration in the original IO group with CLI or GUI.


HyperSwap
When using the HyperSwap function, please configure your host multipath driver to use an ALUA-based path policy. 

Due to the requirement for multiple access IO groups, SAS attached host types are not supported with HyperSwap volumes.

A volume configured with multiple access I/O groups, on a system in the storage layer, cannot be virtualized by a system in the replication layer.  This restriction prevents a HyperSwap volume on one system being virtualized by another.

AIX Live Partition Mobility (LPM) 
AIX LPM is supported with the HyperSwap function and AIX 7.x


Clustered Systems
A SAN Volume Controller system requires native Fibre Channel SAN or alternatively 8Gbps/16Gbps Direct Attach Fibre Channel connectivity for communication between all nodes in the local cluster. Fibre Channel over Ethernet ( FCoE ) connectivity for communication between all nodes in the local cluster is also supported. Clustering can also be accomplished with 25Gbps Ethernet, for standard topologies. For HyperSwap topologies a SCORE request will be required. Please contact your IBM representative to raise a SCORE request.

Partnerships between systems for Metro Mirror or Global Mirror replication can be used with both Fibre Channel, Native Ethernet connectivity and FCoE connectivity, however direct FCoE links are only supported to a maximum of 300 metres. Distances greater than 300 metres are only supported when using an FCIP link or Fibre Channel between source and target.


Direct Attachment
SAN boot on Windows 2019 (Qlogic HBA) is not supported with 32GB direct-attached systems.


Cisco Nexus
The minimum level of Cisco Nexus firmware supported for FCoE with the IBM 2145-DH8 / 2145-SV1 is 5.2(1)N1(2a).


16Gbps Fibre Channel Node Connection
Please see IBM System Storage Inter-operation Center (SSIC) - https://www.ibm.com/systems/support/storage/ssic/interoperability.wss ) for supported 16Gbps Fibre Channel configurations supported with 16Gbps node hardware.

Note 16Gbps Node hardware is supported when connected to Brocade and Cisco 8Gbps or 16Gbps fabrics only.

Direct connections to 2Gbps or 4Gbps SAN or direct host attachment to 2Gbps or 4Gbps ports is not supported.

Other configured switches which are not directly connected to the 16Gbps Node hardware can be any supported fabric switch as currently listed in SSIC.


25Gbps Ethernet Canister Connection
Three optional 2-port 25Gbps Ethernet adapters are supported in each SAN Volume Controller node for iSCSI communication with iSCSI capable Ethernet ports in hosts via Ethernet switches. These 2-port 25Gbps Ethernet adapters do not support FCoE.

There are two types of 25Gbps Ethernet adapter Feature supported:

  1. RDMA over Converged Ethernet (RoCE)
  2. Internet Wide-area RDMA Protocol (iWARP)

Either will work for standard iSCSI communications, i.e. not using Remote Direct Memory Access (RDMA). A future software release will add (RDMA) links using new protocols that support RDMA such as NVMe over Ethernet.

When use of RDMA with a 25Gbps Ethernet adapter becomes possible then RDMA links will only work between RoCE ports or between iWARP ports.

i.e. from a RoCE node canister port to a RoCE port on a host or from an iWARP node canister port to an iWARP port on a host.

The 25Gbps adapters come with SFP28 fitted, which can be used to connect to switches using OM3 optical cables.

For Ethernet switches and adapters supported in hosts see SSIC.

This is an example of a RoCE adapter for use in a host.
http://www.mellanox.com/related-docs/user_manuals/ConnectX-4_Lx_Single_and_Dual_10_25_Gbs_Ethernet_SFP28_Port_Adapter_Card_User_Manual.pdf
This is an example of a iWARP adapter for use in a host.
https://www.chelsio.com/nic/unified-wire-adapters/t6225-cr/

Customers who wish to connect a 10Gb switch to a 25Gb HBA should be aware that this is only supported via a SCORE request. Please contact your IBM representative to raise a SCORE request.


IP Partnership

IP partnerships are supported on any of the available ethernet ports. Using an Ethernet switch to convert a 25Gb to a 1Gb IP partnership, or a 10Gb to a 1Gb IP partnership is not supported. Therefore the IP infrastructure on both partnership sites must match. Bandwidth limiting on IP partnerships between both sites is supported.


Fabric Limitations

Only one FCF ( Fibre Channel Forwarder ) switch per fabric is supported.

Storage connected directly to a Cisco Fabric Extender (FEX) is not supported.


VMware vSphere Virtual Volumes (VVols)

The maximum number of Virtual Machines on a single VMware ESXi host in an SVC / VVol storage configuration is limited to 680.

The use of VMware vSphere Virtual Volumes (VVols) on a system that is configured for HyperSwap is not currently supported with SVC/Storwize.


Host Limitations

N2225/N2226 SAS HBA
VMware 6.7 (Guest O/S SLES12SP4) connected via SAS N2225/N2226 host adapters are not supported.

Lenovo 430-16e/8e SAS HBA
VMware 6.7 and 6.5 (Guest O/S SLES12SP4) connected via SAS Lenovo 430-16e/8e host adapters are not supported.
Windows 2019 and 2016 connected via SAS Lenovo 430-16e/8e host adapters are not supported.

Windows 2016 HyperV
RHEL v7.1 guests on Windows 2016 HyperV, with Virtual Fibre Channel, are not supported.

iSER
Operating systems not currently supported for use with iSER:

  • Windows 2012 R2 using Mellanox ConnectX-4 Lx EN
  • Windows 2016 using Mellanox ConnectX-4 Lx EN

FCoE
Operating systems not currently supported for use with FCoE:

  • RedHat 6.x
  • VMware 6.0
  • Windows 2012 Hyper-V Cluster

Microsoft Offload Data Transfer ( ODX ) and SDDDSM Requirements 
In order to utilise this function all windows hosts accessing SAN Volume Controller are required to be at a minimum SDDDSM version of 2.4.5.0. Earlier versions of SDDDSM are not supported when the ODX function is activated.

Non-Disruptive Volume Move (NDVM) 
Windows 2008 with SDDDSM - Stale paths will be left after moving a volume to a new I/O group. A host reboot is required in order to remove the stale paths. 
AIX 6.1 SDD PCM - Preferred paths are not detected after moving a volume to a new I/O group.

Windows NTP server 
The Linux NTP client used by SAN Volume Controller may not always function correctly with Windows W32Time NTP Server


Oracle 

Oracle Version and OS
Restrictions that apply:
Oracle Release 11.2 any platform
1
Oracle Release 12.1 any platform

Restriction 1
Oracle ASM disk groups may dismount with the following error: 

"Waited 15 secs for write IO to PST"

Recommendation:

Increase the asm_hbeatiowait to 120 seconds to prevent this issue occurring.

Applies to Oracle Database - Enterprise Edition - Version 11.2.0.3 to 12.1.0.1 [Release 11.2 to 12.1] on any platform 
 


Priority Flow Control for iSCSI/iSER

Priority Flow Control for iSCSI/iSER is supported on Emulex & Chelsio adapters (SVC supported) with all DCBX enabled switches.


Maximum Configurations

Configuration limits for SAN Volume Controller:

Property 
Hardware Type 
Maximum Number
Notes 
System (Cluster) Properties
Nodes per system (cluster)
8
Arranged as four I/O groups
Nodes per fabric
64
Maximum number of SVC or Storwize family system nodes that can be present on the same Fibre Channel fabric, with visibility of each other
I/O groups per system
4
Each containing two nodes
Fabrics per system
12
The number of counterpart SANs which are supported
Inter-cluster partnerships per system

(maximum 1 IP partnership is supported)
A system may be partnered with up to three remote systems. No more than four systems may be in the same connected set
IP Quorum devices per system
5
Data encryption keys per system
1024
Node Properties
Logins per node Fibre Channel WWPN
512
Includes logins from server HBAs, disk controller ports, node ports within the same system and node ports from remote systems
Fibre Channel buffer credits per port
8Gbps FC Adapter
255
The number of credits granted by the switch to the node
16Gbps FC Adapter
4095
iSCSI sessions per node
1024
A maximum of 256 can be backend sessions.
This limit includes both iSCSI Host Attach AND iSCSI Initiator sessions
iSER sessions per node
256
Model SV1 only
Managed Disk Properties
Managed disks (MDisks) per system
4096
The maximum number of logical units which can be managed by a cluster.

Internal distributed arrays consume 16 logical units.

This number includes external MDisks which have not been configured into storage pools (managed disk groups)
Managed disks per storage pool (managed disk group)
128
Storage pools per system
1024
Parent pools per system
128
Child pools per system
1023
Not supported in a Data Reduction Pool
Managed disk extent size
8192 MB
Capacity for an individual internal managed disk (array)
-
No limit is imposed beyond the maximum number of drives per array limits.
Maximum size is dependent on the extent size of the Storage Pool.
Comparison Table: Maximum Volume, MDisk and System capacity for each extent size.
Capacity for an individual external managed disk
1 PB
Note: External managed disks larger than 2 TB are only supported for certain types of storage systems. Refer to the supported hardware matrix for further details.
Maximum size is dependent on the extent size of the Storage Pool.
Comparison Table: Maximum Volume, MDisk and System capacity for each extent size.
Total storage capacity manageable per system
32 PB
Maximum requires an extent size of 8192 MB to be used

This limit represents the per system maximum of 2^22 extents.

Maximum size is dependent on the extent size of the Storage Pool.
Comparison Table: Maximum Volume, MDisk and System capacity for each extent size.
Data Reduction Pool Properties
Data Reduction Pools per system
4
Mdisks per Data Reduction Pool
128
Volume copies per Data Reduction Pool
10000 - (Number of Data Reduction Pools x 12)
Extents per I/O group per Data Reduction Pool
128000
Volume (Virtual Disk) Properties
Basic volumes (VDisks) per system
10000
Each basic volume uses 1 VDisk, each with one copy.
Stretched volumes per system
5000
Each stretched volume uses 1 VDisk, each with two copies.
HyperSwap volumes per system
1250
Each HyperSwap volume uses 4 VDisks, each with one copy, 1 active-active remote copy relationship and 4 FlashCopy mappings.
Volumes per I/O group
(volumes per caching I/O group)
10000
Volumes accessible per I/O group
10000
Thin-provisioned (space-efficient) volume copies in regular pools per system
-
No limit is imposed here beyond the volume copies per system limit.
Compressed volume copies in regular pools per system
2048
Maximum requires an 8-node cluster
Compressed volume copies in regular pools per I/O group
512
With 64GB Memory Option Only
Compressed volume copies in data reduction pools per system
-
No limit is imposed here beyond the volume copy limit per data reduction pool
Compressed volume copies in data reduction pools per I/O group
-
No limit is imposed here beyond the volume copy limit per data reduction pool
Deduplicated volume copies in data reduction pools per system
-
No limit is imposed here beyond the volume copy limit per data reduction pool
Deduplicated volume copies in data reduction pools per I/O group
-
No limit is imposed here beyond the volume copy limit per data reduction pool
Volumes per storage pool
-
No limit is imposed beyond the volumes per system limit
Fully-allocated volume capacity
256 TB
Maximum size for an individual fully-allocated volume.

Maximum size is dependent on the extent size of the Storage Pool.
Comparison Table: Maximum Volume, MDisk and System capacity for each extent size.
Thin-provisioned (space-efficient) per-volume capacity for volumes in regular and data reduction pools
256 TB
Maximum size for an individual thin-provisioned volume

Maximum size is dependent on the extent size of the Storage Pool.
Comparison Table: Maximum Volume, MDisk and System capacity for each extent size.
Compressed volume capacity in regular pools Pools containing non-Flash storage
16 TB
Maximum size for an individual compressed volume.

See this Flash for further information on this limit.

Maximum size is dependent on the extent size of the Storage Pool.
Comparison Table: Maximum Volume, MDisk and System capacity for each extent size.
Pools containing all-Flash storage
32 TB
Host mappings per system
64,000
See also - volume mappings per host object below
Mirrored Volume (Virtual Disk) Properties
Copies per volume
2
Volume copies per system
10000
The maximum number of volumes cannot all have the maximum number of copies
Total mirrored volume capacity per I/O group
1024 TB
Host Properties
Host objects (IDs) per system
2048
Host objects (IDs) per I/O group
512
Volume mappings per host object
2048
Although SVC allows the mapping of up to 2048 volumes per host object, not all hosts are capable of accessing/managing this number of volumes. The practical mapping limit is restricted by the host OS, not SVC.
Note: this limit does not apply to hosts of type adminlun (used to support VMware vvols).
Host Cluster Properties
Host clusters per system
512
Hosts in a host cluster
128
Fibre Channel Host Properties (including hosts attached using FCoE)
Fibre Channel hosts per system
2048
Fibre Channel host ports per system
8192
Fibre Channel hosts per I/O group
512
Fibre Channel host ports per I/O group
2048
Fibre Channel host ports per host object (ID)
32
Simultaneous I/Os per node FC port
8Gbps FC Adapter
2048
16Gbps FC Adapter
4096
iSCSI Host Properties
iSCSI hosts per system
2048
iSCSI hosts per I/O group
512
iSCSI names per host object
4
iSCSI names per I/O group
512
iSCSI (SCSI 3) registrations per VDisk
512
iSER Host Properties
iSER hosts per system
2048
Model SV1 only.
iSER hosts per I/O group
512
Model SV1 only.
iSER names per host object
4
Model SV1 only
iSER (SCSI 3) registrations per VDisk
1024
Model SV1 only
NVMe over Fibre Channel Host Properties
FC-NVMe hosts per system
32
Up to 32 FC-NVMe hosts are supported per system.
This limit is not policed by the Spectrum Virtualize software. Any configurations that exceed this limit may experience significant adverse performance impact.
FC-NVMe hosts per I/O group
16
This limit is not policed by the Spectrum Virtualize software. Any configurations that exceed this limit may experience significant adverse performance impact.
NVMe Qualified Names (NQNs) per host object (ID)
2
Copy Services Properties
Remote Copy (Metro Mirror and Global
Mirror) relationships per
system
10000
This can be any mix of Metro Mirror and Global Mirror relationships.
Maximum requires an 8-node cluster
Active-Active Relationships (HyperSwap)
1250
Remote Copy relationships per consistency group (<=256 GMCV relationships configured)
-
No limit is imposed beyond the Remote Copy relationships per system limit
Remote Copy relationships per consistency group (>256 GMCV relationships configured)
200
Remote Copy consistency
groups per system
256
Total Metro Mirror and Global Mirror volume capacity per I/O group
1024 TB
This limit is the total capacity for all master and auxiliary volumes in the I/O group.
Total number of Global Mirror with Change Volumes relationships per system
2145-DH8
256
60s cycle time (Change volumes used for active-active relationships do not count towards this limit).
1500
300s cycle time (Change volumes used for active-active relationships do not count towards this limit).
2145-SV1
256
60s cycle time (Change volumes used for active-active relationships do not count towards this limit).
2500
300s cycle time (Change volumes used for active-active relationships do not count towards this limit).
FlashCopy mappings per system
5000
FlashCopy targets
per source
256
FlashCopy mappings
per consistency group
512
FlashCopy consistency groups per system
500
Total FlashCopy volume capacity per I/O group
4096 TB
3-site Remote Copy (Metro Mirror) relationships per consistency group
256
3-site Remote Copy (Metro Mirror) consistency groups per system
16
3-site Remote Copy (Metro Mirror) relationships per system
1250
IP Partnership Properties
Inter-cluster IP partnerships per system
1
A system may be partnered with up to three remote systems. A maximum of one of those can be IP and the other two FC.
I/O groups per system
2
The nodes from a maximum of two I/O groups per system can be used for IP partnership.
Inter site links per IP partnership
2
A maximum of two inter site links can be used between two IP partnership sites.
Ports per node
1
A maximum of one port per node can be used for IP partnership.
IP Partnership Software Compression Limit
2145-DH8
2145-SV1
140 MB/s
Internal Storage System Properties
Max expansion enclosures per I/O group
20
The limiting factor is the combined chain weight of the various components. The maximum SAS chain weight that can be attached to a node SAS port is 10:
2145-92F enclosures have a chain weight of 2.5;
2145-24F and 2145-12F enclosures have a chain weight of 1.
Max drives per enclosure
92
Max drives per I/O group
736
Max drives per system
2944
Non-Distributed RAID Array Properties
Min-Max member drives per RAID-0 array
1-8
Min-Max member drives per RAID-1 array
2-2
Min-Max member drives per RAID-5 array
3-16
Min-Max member drives per RAID-6 array
5-16
Min-Max member drives per RAID-10 array
2-16
Distributed RAID Array Properties
Arrays per system
32
The presence of non-DRAID arrays will reduce this limit
Encrypted arrays per system
32
The presence of non-DRAID arrays will reduce this limit
Arrays per I/O group
10
The presence of non-DRAID arrays will reduce this limit
Drives per array
48
Min-Max member drives per RAID-5 array
4-48
Min-Max member drives per RAID-6 array
6-48
Rebuild areas per array
1-4
Min-Max stripe width for RAID-5 array
3-16
Min-Max stripe width for RAID-6 array
5-16
Drives added to an array in a single DRAID expansion
12
Concurrent DRAID expansions per system
4
Concurrent DRAID expansions per parent storage pool
1
External Storage System Properties
Storage system WWNNs per system (cluster)
1024
Storage system WWPNs per system (cluster)
1024
WWNNs per storage system
16
WWPNs per WWNN
16
LUNs (managed disks) per storage system
-
No limit is imposed beyond the managed disks per system (cluster) limit
System and User Management Properties
User accounts per system
400
Includes the default user accounts
User groups per system
256
Includes the default user groups
Authentication servers per system
1
NTP servers per system
1
iSNS servers per system
1
Concurrent open SSH sessions per system
32
Event Notification Properties
SNMP servers per system
6
Syslog servers per system
6
Email (SMTP) servers per system
6
Email servers are used in turn until the email is successfully sent
Email users (recipients) per system
12
LDAP servers per system
6
REST API Properties
Threads per session
64
HTTP header size
16 KB
Response objects
2000
2145-DH8 Hardware Properties
8Gbps Fibre channel cards per node
4
16Gbps Fibre channel cards per node
4
Compression accelerator cards per node
2
10Gbps Ethernet adapters per node
2
10Gbps Ethernet ports per node
8
FCoE is supported on the first four 10GbE ports in the system
1Gbps Ethernet ports per node
3
2145-SV1 Hardware Properties
16Gbps Fibre channel cards per node
4
Compression accelerator cards per node
2
10Gbps Ethernet cards per node
1
10Gbps Ethernet optical ports per node
4
10Gbps Ethernet copper ports per node
3
25Gbps Ethernet adapters per node
3
Ethernet adapters that can be used per node
11
Not counting the dedicated Technician port which cannot be used for iSCSI
2145-SV1 iSER Hardware Properties
25Gbps iWARP adapters per node
4
25Gbps ROCE adapters per node
4
25Gbps iWARP ports per node
8
25Gbps ROCE ports per node
8
 

Extents

The following table compares the maximum volume, MDisk and system capacity for each extent size.

Extent size (MB) 
Maximum non thin-provisioned volume capacity in GB
Maximum thin-provisioned volume capacity in GB (for regular pools) 
Maximum compressed volume size (for regular pools) ** 
Maximum thin-provisioned and compressed volume size in data reduction pools in GB
Maximum total thin-provisioned and compressed capacity for all volumes in a single data reduction pool per IOgroup in GB
Maximum MDisk capacity in GB 
Maximum DRAID Mdisk capacity in TB 
Total storage capacity manageable per system* 
16
2048 (2 TB)
2000
2TB
2048 (2 TB)
2048 (2 TB)
2048 (2 TB)
32
64 TB
32
4096 (4 TB)
4000
4TB
4096 (4 TB)
4096 (4 TB)
4096 (4 TB)
64
128 TB
64
8192 (8 TB)
8000
8TB
8192 (8 TB)
8192 (8 TB)
8192 (8 TB)
128
256 TB
128
16,384 (16 TB)
16,000
16TB
16,384 (16 TB)
16,384 (16 TB)
16,384 (16 TB)
256
512 TB
256
32,768 (32 TB)
32,000
32TB
32,768 (32 TB)
32,768 (32 TB)
32,768 (32 TB)
512
1 PB
512
65,536 (64 TB)
65,000
64TB
65,536 (64 TB)
65,536 (64 TB)
65,536 (64 TB)
1024 (1 PB)
2 PB
1024
131,072 (128 TB)
130,000
96TB ** 
131,072 (128 TB)
131,072 (128 TB)
131,072 (128 TB)
2048 (2 PB)
4 PB
2048
262,144 (256 TB)
260,000
96TB ** 
262,144 (256 TB)
262,144 (256 TB)
262,144 (256 TB)
4096 (4 PB)
8 PB
4096
262,144 (256 TB)
262,144
96TB ** 
262,144 (256 TB)
524,288 (512 TB)
524,288 (512 TB)
8192 (8 PB)
16 PB
8192
262,144 (256 TB)
262,144
96TB ** 
262,144 (256 TB)
1,048,576 (1024 TB)
1,048,576 (1024 TB)
16384 (16 PB)
32 PB


* The total capacity values assumes that all of the storage pools in the system use the same extent size. 
** Please see the  following Flash

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Document Information

Modified date:
29 July 2020

UID

ibm11098819