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IBM FlashSystem A9000Version 12.3.2.a

Release Notes

IBM

Sixth Edition (January 2020)

This edition applies to IBM FlashSystem® A9000 version 12.3.2.a. Newer document editions may be issued for the sameproduct version in order to add missing information, update information, or amend typographical errors. The edition isreset to 'First Edition' for every new product version.© Copyright International Business Machines Corporation 2016, 2020.US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract withIBM Corp.

Contents

Overview...............................................................................................................1

What's new in version 12.3.2.a.............................................................................. 3

Hot upgrade from earlier versions.......................................................................... 5

Management and solutions.................................................................................... 7

Change log............................................................................................................ 9Version 12.3.2.a (August 2019).................................................................................................................. 9Version 12.3.2 (May 2019)........................................................................................................................ 12Version 12.3.1 (January 2019)..................................................................................................................13Version 12.3.0.a (November 2018)...........................................................................................................14Version 12.3.0 (November 2018)..............................................................................................................14

Fixes and features of earlier versions................................................................... 21

Limitations.......................................................................................................... 23

Known issues...................................................................................................... 25

Known interoperability issues..............................................................................33

Related information and publications...................................................................35

Getting information, help, and service..................................................................37

Notices................................................................................................................39Trademarks................................................................................................................................................ 40

iii

OverviewIBM FlashSystem A9000 is a compact, small-footprint, all-flash storage system that delivers ultra-faststorage together with mission-critical features, including data reduction by compression and inlinededuplication, smart scaling, distributed data, automatic load balancing, and a multitude of advancedenterprise-class features and capabilities.

Built as a rack-free modular unit, IBM FlashSystem A9000 can utilize existing infrastructure (such asracks, power distribution units, and more) and can be hyper-scaled with additional IBM FlashSystemA9000 units that could be added to the enterprise storage infrastructure over time.

In its core architecture, IBM FlashSystem A9000 utilizes IBM FlashCore® technology together with IBM®

MicroLatency® modules, providing high density, low latency, and high IOPS performance. In addition, IBMFlashSystem Enhanced Endurance Technology reduces flash disk wearout and ensures long-termdurability of the flash storage components, even under heavy workloads.

IBM FlashSystem A9000 is ideal for enterprise cloud environments that require fast, reliable, andredundant data storage, offering high service levels for dynamic workloads and easy hyper-scaling, whilesupporting multi-tenant environments, flexible consumption models, and robust cloud automation andintegration capabilities. IBM FlashSystem A9000 offers data protection through advanced remotemirroring, including synchronous mirroring, asynchronous mirroring, and HyperSwap® high availabilitythrough active-active pairing. It also helps protect data with encryption and a range of data securityfeatures.

For more detailed information about IBM FlashSystem A9000, refer to its user documentation and onlineinformation.

© Copyright IBM Corp. 2016, 2020 1

2 IBM FlashSystem A9000: Release Notes

What's new in version 12.3.2.aSoftware version 12.3.2.a enhances the operation of existing functional features and resolvesmiscellaneous issues.

General availability (eGA) date: 19 August 2019

For information about the resolved issues in version 12.3.2.a, see “Change log” on page 9.


Hot upgrade from earlier versionsSoftware version 12.3.2.a supports direct non-disruptive upgrade (hot upgrade) of IBM FlashSystemA9000 from the following versions.

• 12.3.0.a, 12.3.1, 12.3.2• 12.2.0.b, 12.2.1.b-1, 12.2.1.b-2• 12.1.0.b, 12.1.0.d• 12.0.3.b

Note: These hot upgrade paths are valid for the time of the general availability (eGA) date of version12.3.2.a. However, hot upgrade from additional earlier versions could be supported later on. For up-to-date information, contact IBM Support.

The upgrade procedure must be performed by an authorized IBM service technician.

Prior to initiating software upgrade, consult with IBM Support regarding the required time allocation andexpected duration of the upgrade procedure.

Note: The system e-license may automatically prompt in the management GUI upon the first post-upgrade operation, if the e-license was updated since it was last accepted. In such a case, the new e-license must be accepted before any GUI operation can be performed.


Management and solutionsIBM FlashSystem A9000 version 12.3.2.a can be managed and monitored with IBM Hyper-Scale Managerversion 5.5.2 or later.

IBM Hyper-Scale Manager version 5.5.2 provides an advanced web-based graphical user interface (GUI)from which one or more IBM Spectrum Accelerate Family systems can be managed and monitored in realtime from a web browser.

Note: Versions of IBM Hyper-Scale Manager earlier than 5.5.2 are not fully supported and must beupgraded to 5.5.2 or later.

IBM FlashSystem A9000 can also be managed from its command-line interface (CLI) or throughrepresentational state transfer (REST) application programming interfaces (APIs).

IBM FlashSystem A9000 customers are entitled to free use of IBM Hyper-Scale Manager, which can beobtained at any time from the IBM Fix Central website (www.ibm.com/support/fixcentral).

IBM Spectrum Accelerate Family HyperSwap Quorum Witness

The HyperSwap functionality feature in IBM FlashSystem A9000 version 12.3.2.a is supported by IBMSpectrum Accelerate Family HyperSwap Quorum Witness version 1.0.2 or later.

To significantly improve the transparent failover and facilitate the constant coordination between twoIBM FlashSystem A9000 or A9000R storage systems in a HyperSwap solution, an independent QuorumWitness software component is preferably installed at a separate site (third failure domain).

Important: Quorum Witness cannot reside on the same set of FlashSystem A9000 and/or A9000Rsystems of which it serves as part of a HyperSwap configuration.

Note: Newer versions of the Quorum Witness software may be released independently to better supportor enhance the HyperSwap operation. For more information, see the latest Quorum Witness releasenotes and user guide.

IBM block storage CSI driver

IBM FlashSystem A9000 version 12.3.2.a is supported by IBM block storage CSI driver version 1.0.0. TheCSI (Container Storage Interface) driver is leveraged by Kubernetes persistent volumes (PVs) todynamically provision for block storage used with stateful containers. IBM block storage CSI driver isbased on an open-source IBM project (CSI driver) (https://github.com/ibm/ibm-block-csi-driver),included as a part of IBM storage orchestration for containers.

The CSI driver can be downloaded, installed, and configured through the Red Hat OperatorHub or fromDocker Hub, through a command line terminal.

For more information, see IBM block storage CSI driver on IBM Knowledge Center (ibm.com/support/knowledgecenter/SSRQ8T).

IBM Spectrum Connect

IBM FlashSystem A9000 version 12.3.2.a is supported by IBM Spectrum® Connect version 3.6.0 or later,which provides the following platform integration tools.

• IBM Storage Provider for VMware VASA• IBM Storage Enhancements for VMware vSphere Web Client• IBM Storage Plug-in for VMware vRealize Orchestrator


http://www.ibm.com/support/fixcentral

https://github.com/ibm/ibm-block-csi-driver

https://www.ibm.com/support/knowledgecenter/SSRQ8T

• IBM Storage Management Pack for VMware vRealize Operations Manager• IBM Storage Automation Plug-in for Microsoft PowerShell• IBM Storage Enabler for Containers

For more information, see IBM Spectrum Connect on IBM Knowledge Center (www.ibm.com/support/knowledgecenter/SS6JWS), and the IBM Spectrum Connect marketing page (www.ibm.com/us-en/marketplace/spectrum-connect).

IBM FlashSystem A9000 customers are entitled to free use of IBM Spectrum Connect, which can beobtained at any time from either the IBM Hyper-Scale Manager software package or from the IBM FixCentral website (www.ibm.com/support/fixcentral).

Available cloud storage solutions

IBM FlashSystem A9000 version 12.3.2.a can be integrated with various independent software vendor(ISV) platform, application, virtualization, and cloud environments.

To facilitate this integration, IBM provides the following software solutions, also referred to as cloudstorage solutions.

Cloud storage solution Version Compatibility note

IBM Storage Host Attachment Kit 2.9.0 or later For use with IBM AIX®, Linux (Red HatEnterprise Linux; SUSE Linux EnterpriseServer), and Microsoft Windows Serverhosts.

IBM Storage Driver for OpenStack 2.3.0 or later For use with OpenStack Cinder(OpenStack Block Storage) nodes

IBM Storage Management Pack forMicrosoft System Center OperationsManager (SCOM)

2.7.0 or later

IBM Spectrum Accelerate FamilyProvider for Microsoft Windows VolumeShadow Copy Service (VSS)

2.10.0 or later

IBM Spectrum Accelerate Family StorageReplication Adapter (SRA)

3.0.1 or later For use with VMware Site RecoveryManager 6.x or later. Requires the use ofsynchronous or asynchronous remotemirroring.

IBM FlashSystem A9000 customers are entitled to free use of the IBM cloud storage solutions, which canbe obtained at any time from the IBM Fix Central website (www.ibm.com/support/fixcentral).

For more information about the available cloud storage solutions for IBM FlashSystem A9000, see the'Platform and application integration' section in the IBM FlashSystem A9000 space on IBM KnowledgeCenter (www.ibm.com/support/knowledgecenter/STJKMM).


http://www.ibm.com/support/knowledgecenter/SS6JWS

https://www.ibm.com/us-en/marketplace/spectrum-connect




http://www.ibm.com/support/knowledgecenter/STJKMM


Change logThis change log summarizes the enhancements and fixes in the different 12.3.x code level versions ofIBM FlashSystem A9000.

Note: New functional features of these versions are only briefly summarized. For a detailed summary ofthe new functional features of a specific version, refer to the 'What's new' section of its release notes.

Version 12.3.2.a (August 2019)Software version 12.3.2.a resolves the following issues.

Ticket ID Description

SYS-313410 Fixed: In rare cases, a cluster attempt to isolate a failing component may fail,causing the cluster to wrongly shut down the component, leading to extendedmaintenance time.

Severity: HIPER

Affected versions: 12.0.0 or later

SYS-309772 Fixed: Common security issue. For more information about this security issue,see (CVE-2017-17833) on the Common Vulnerabilities and Exposures (CVE)information website (cve.mitre.org).

Severity: High Impact


SYS-313717 Fixed: In rare cases, a MicroLatency module communication error couldsometimes cause loss of access due to a rare timing condition, resulting in agraceful emergency shutdown of the system.



SYS-315184 Fixed: In rare cases, in a Multi-site HA DR relation, a required failover will notoccur due to a problem with the primary system, following a disconnectedservice reporting an incorrect peer health status.



SYS-314004 Fixed: In extremely rare cases, when the system is undergoing heavy SCSIunmap loads combined with excessive write operations, write performance willbe affected. The system resumes normal performance once the heavy unmapoperations complete.




https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-17833


SYS-315076 Fixed: In extremely rare cases, a switch role during a temporary disconnectbetween the primary system and Quorum Witness, in addition to a uniquesequence of events, a failover, if required, may not be able to be performed. Anexample of the type of sequence of events could be a connectivity issuebetween the primary and secondary volumes in a Multi-Site HA DR relationoccurring prior to the above temporary disconnection from the Quorum Witnessand the unique sequence of events.



SYS-315195 Fixed: Common security issue. For more information about these securityissues, see CVE-2019-11477 , CVE-2019-11478, and CVE-2019-11479 on theCommon Vulnerabilities and Exposures (CVE) information website(cve.mitre.org).



SYS-310286 Fixed: If the storage system has reached its maximum storage capacity,performance for user reads and remote mirroring might be degraded.

Severity: Moderate


SYS-310912 Fixed: When using the host_remove_port CLI command on a port designatedfor a HyperSwap volume, the command should remove the port on both thelocal and the remote systems. Instead, only the local system port is removedand the virtual port on the remote system remains configured for theHyperSwap volume. This can also expose the volume to SCSI reservationconflict until the virtual port is manually removed.

Severity: Moderate


SYS-310952 Fixed: In rare cases, deleting an asynchronous mirror relation that is part of async job batch immediately after start, causes other sync jobs to the sameremote target to get stuck. These sync job prolonged delays can be seen byusing the sync_job_list CLI command.

Severity: Moderate


SYS-311218 Fixed: When a volume has more than 10 user metadata items, the initial syncoccurring after the creation of an IBM Hyper-Scale Mobility or HyperSwaprelation may fail and management operations may not run on the system. Thiscan be seen when performing various CLI commands and receiving theMCL_NETWORK_ERROR return code.

This does not impact any I/O operations.

Note: Note: In order to check how many metadata items are listed on a specificvolume, use the metadata_list CLI command.

Severity: Moderate







SYS-314736 Fixed: In rare cases, in a Multi-site relation environment which includes manymirroring relations, a target reconnection may cause some I/O delays.

Severity: Moderate


SYS-314991 Fixed: In rare cases following specific software failures on a secondary system,when using synchronous mirroring and the volume is part of a consistencygroup, management operations on the primary system will not run.

Severity: Moderate


SYS-315015 Fixed: In some cases, due to an issue in the internal communication, a faultyFLASH_CANISTER_ETH_LINK_MISWIRE event is emitted. After approximatelyone hour, this event is followed by the correctingFLASH_CANISTER_ETH_WIRING_OK event.

Severity: Moderate


SYS-315029 Fixed: In a Multi-site HA/DR configuration, a user will not be able to add a Multi-site volume into a consistency group, if the following order of events haveoccurred:

1. A standby replication relation was activated for a specific consistency group.2. A role change occurred.3. The new relation is not yet been activated for this consistency group.

Severity: Moderate


SYS-315146 Fixed: Flash enclosure daily snap collections may result in momentary latencyincrease.

Severity: Moderate

Affected versions: 12.3.2.a

SYS-310343 Fixed: The status of the backup battery unit (BBU) in the flash enclosure mightbe shown as failed while it is still operating normally. If this occurs, contact IBMSupport.

Severity: Service


SYS-314453 Fixed: In rare cases, latency spikes in system statistics might unnecessarily beemitted. This is a false identification and can be ignore. This behavior has noactual impact on system performance.

Severity: Service


Change log 11

Version 12.3.2 (May 2019)Software version 12.3.2 added support for virtual LAN (VLAN) capabilities, and resolved the followingissues.


SYS-313334 Fixed: In rare conditions, a bug in the microcode might lead to undetected datacorruption (a range of 16 MB returning old data instead of zeros), on theSecondary volume of any type of mirroring relationship: synchronous mirroring,asynchronous mirroring, HyperSwap, or Multi-site HA DR.

Severity: HIPER


SYS-313522 Fixed: In rare cases, a CPU error might lead to a SCSI MEDIUM ERRORcondition.



SYS-308548 Fixed: In a HyperSwap relation, when a remote system target is deleted andthen redefined, creating new HyperSwap relations on this target system is notpossible.

Severity: Moderate


SYS-310148 Fixed: In rare cases, due to a unique chain of events resulting in an internalresource depletion, disconnected Fibre Channel hosts may not be able toautomatically reconnect.

Severity: Moderate


SYS-310990 Fixed: In rare cases where an internal process fails, the reported connectivityfor FC or iSCSI hosts might be wrong when running thehost_connectivity_list and fc_connectivity_list CLI commands.

Severity: Service


SYS-311467 Fixed: Statistics information is not kept for target ports in mirror relations.

Severity: Service



Version 12.3.1 (January 2019)Software version 12.3.1 of IBM FlashSystem A9000 introduced deduplication-aware capacitymanagement (available via IBM Hyper-Scale Manager 5.5.1 or later) and resolved the following issues.


SYS-310338 Fixed: In rare cases, for a system with encryption enabled:

1. During a replacement procedure of a malfunctioning MicroLatency module,the procedure might fail and the new MicroLatency module might stay offline,thus compromising the system redundancy.

2. During firmware upgrade of the flash enclosure, the procedure might halt andthe flash enclosure upgrade can not complete.

In both of the cases described above, a maintenance window might have to bescheduled for a complete restart of the system.

Severity: HIPER


SYS-310091 Fixed: In rare cases, a flash RAID controller malfunction and a particular writeerror might cause MicroLatency modules on the flash enclosure to fail, leadingto loss of access to the storage system.



SYS-308309 Fixed: In rare cases, a replacement of a flash canister in the storage systemmight cause performance degradation.

Severity: Moderate


SYS-309381 Fixed: In rare cases, an InfiniBand interconnect issue might lead toperformance degradation.

Severity: Moderate


SYS-311260 Fixed: If performance classes are used, the I/O bandwidth allocation that isassociated with some performance classes might be incorrectly calculated. Thiscould lead to incorrect performance limits for hosts or volumes.

Severity: Moderate


SYS-311325 Fixed: If the size of a written volume and its snapshots is larger than the totalvolume size, the vol_list CLI command shows only the volume total size,without the size of the volume snapshots.

Severity: Service


Change log 13

Version 12.3.0.a (November 2018)Software version 12.3.0.a of IBM FlashSystem A9000 resolved the following issues.


SYS-309775 Fixed: In rare cases, after software upgrade on a system of model 425, thesystem might experience growing latencies in I/O operations, until all hosts loseaccess to the storage system.

Severity: HIPER

Affected versions: 12.3.0

SYS-310311 Fixed: In rare cases, systems that are using snapshots or asynchronous remotemirroring might disconnect when a volume deletion operation is performed. Insuch a case, the DATA_REDUCTION_TIER_BECOMING_OFFLINE event islogged.



Version 12.3.0 (November 2018)Software version 12.3.0 of IBM FlashSystem A9000 added the following functional features.

• Multi-site high availability (HA) and disaster recovery (DR).• Removal of storage pool size limitation (was 1 PB).• Monitor internal/external latency at the system level.• Pending deletion indication.• Option for using a longer user password of up to 64 characters.

Version 12.3.0 also resolved the following issues.


SYS-307098 Fixed: In a HyperSwap setup with an active SCSI reservation, if only a subset ofthe host ports that are defined on the System holding the Primary volume, isdefined on the System which holds the Secondary volume, the latter systemmight not conform to the SCSI reservation. As a result, the Secondary volumemight be read by another host; and after a HyperSwap failover, the new Primaryvolume (former Secondary volume) might be written to by another host. Thisviolation of SCSI reservation will be undetected.

Severity: HIPER


SYS-305091 Fixed: In rare cases, using the io_pause CLI command might cause loss ofaccess to the storage system.





SYS-305121 Fixed: When using IBM Hyper-Scale Mobility and the volume migration is inProxy state, a broken link to the destination system might cause hosts to loseaccess to one or more of the Proxy-state interface modules.



SYS-306002 Fixed: In rare cases, a noisy network over FC connectivity might disrupt themirroring relation between two A9000 systems over FC connectivity, causingrepeated loops of disconnection and connection between the two systems.



SYS-306086 Fixed: When most of the physical memory of the storage system is occupied bydifferent operation processes, deleting a significant amount of obsolete dataand then restarting I/O operations before the data garbage collection processhas completed - might result in loss of access of hosts to the storage system.



SYS-306139 Fixed: Before a hot upgrade, all primary HyperSwap volumes must bedeactivated in order to make the secondary volumes unavailable. Otherwiselocal I/O operations during the hot upgrade will be blocked.



SYS-306457 Fixed: In rare cases, the data redistribution after the addition of a grid elementmight fail due to a data transfer error. If this occurs, hot upgrade of the storagesystem software will not be possible.



SYS-306775 Fixed: The iSCSI port driver might crash when invalid data length is specified ina read or write I/O command, causing loss of access of all iSCSI hosts to thestorage system.



SYS-307087 Fixed: Common security issues.

For more information about these security issues, see CVE-2016-3672,CVE-2017-9725, CVE-2017-12190, CVE-2017-14140, CVE-2017-15126,CVE-2017-17449, CVE-2017-17558, CVE-2017-18017, and CVE-2018-6927on the Common Vulnerabilities and Exposures (CVE) information website(cve.mitre.org).



Change log 15











SYS-307118 Fixed: In rare cases, a HyperSwap relation might get disconnected when tryingto synchronize SCSI registrations between the Primary and the Secondarysystems.



SYS-307609 Fixed: If InfiniBand connections between the grid controller and the flashenclosure in an A9000 system are wired incorrectly, hot upgrade of the storagesystem might cause hosts to lose access the storage system. The same mighthappen if the storage system is already running, and the wiring is changedincorrectly.



SYS-307626 Fixed: In rare cases, a storage system might fail to isolate a failing component,but wrongly detect that the component is successfully isolated. This mightresult in hosts losing access to the storage system, or in data unavailability.


Affected versions: 12.0.0.a or later

SYS-307692 Fixed: In extremely rare cases, a grid controller might not be able to exchangedata with one of the flash enclosures, leading to a severe impact onperformance, and possibly also to loss of access to the storage system.



SYS-307426 Fixed: In a HyperSwap relation, a host issuing a LUN reset task might causefailure of all subsequent reservation operations, causing the HyperSwap relationto break.



SYS-307854 Fixed: In rare cases, after performing hot upgrade while using Fibre Channel(FC) connectivity, the FC driver process might crash and then restartautomatically. In some system or host configurations, this might result in hostslosing access to the storage system.



SYS-307715 Fixed: In rare cases, when hosts are connected to the storage system via iSCSI,a Send Targets request (sent from a host) might cause a loss of access for allhosts connected to the storage system.





SYS-307743 Fixed: In rare cases, after the recovery of a failed software component, theconnectivity to a remote mirroring target might not be restored.



SYS-307987 Fixed: In rare cases, when using asynchronous mirroring, specific writesequences (writes of 0) combined with a mirror deactivation procedure mayresult in loss of access upon re-activation. On even rarer occasions, loss of datacan occur.



SYS-308098 Fixed: In rare cases, if the hot upgrade of a storage system that is usingencryption is canceled, an internal component failure might trigger anemergency shutdown procedure, following by loss of access by hosts to thestorage system.



SYS-308517 Fixed: A grid controller might get disconnected due to a rare software processfailure. If two grid controllers get disconnected simultaneously, an emergencyshutdown procedure will be initiated.



SYS-304905 Fixed: When performing a system wipe-out operation and then disabling thesystem's data encryption (for example, for the purpose of moving the systemoff-premise), the system performs several emergency shutdowns before theencryption disabling is completed.

Severity: Moderate


SYS-306078 Fixed: In rare cases, I/O operations might be rejected due to an IOPS orbandwidth limit of a QoS performance class, even though these I/O operationsare not subject to any QoS performance class limitation.

Severity: Moderate


SYS-306353 Fixed: Mirrored volumes that are not part of a consistency group (CG) cannotbenefit from the 12.2.0 software enhancements that allow configuring an RPOof 1 minute and mirroring interval of 20 seconds.

Severity: Moderate


Change log 17


SYS-306627 Fixed: In rare cases, after a hot upgrade of a Primary system in a HyperSwaprelationship over Fibre Channel (FC) connectivity, the FC driver process mightcrash and then restart automatically, causing temporary HyperSwapconnectivity disconnection.

Severity: Moderate


SYS-307088 Fixed: In rare cases, the size of the volume in the data migration source mightbe incorrectly reported when using the dm_define or the dm_activate CLIcommands. If this occurs, data migration cannot be performed.

Severity: Moderate

Affected versions: 12.0.3.b or later

SYS-307675 Fixed: In rare cases, internal disconnections between a grid controller and theflash enclosure might increase the latency. If this occurs, theIO_TOOK_TOO_LONG event is logged.

Severity: Moderate


SYS-307815 Fixed: In rare cases, a particular sequence of read and write I/O operationsmight cause performance degradation.

Severity: Moderate


SYS-280653 Fixed: Some CLI commands might hang when storage pools are being cleanedfrom snapshots.

Severity: Service


SYS-305312 Fixed: When using HyperSwap, the HA_MASTER_UNAVAILABLE andHA_MASTER_AVAILABLE system events are not logged for all volumes andconsistency groups after a system reboot followed by disconnection from thepeer system. As a result, incorrect values are shown when using the ha_listcommand as long as the disconnection continues.

Severity: Service


SYS-305901 Fixed: In rare cases, after a reboot or software upgrade of the storage system,the output of the fan_list CLI command might list fans as failed, even thoughthe fans are fully operational.

Severity: Service


SYS-307419 Fixed: If the storage system stores secondary HyperSwap volumes, hot upgradeof this storage system might fail if the HyperSwap relation is not disabledbeforehand.

Severity: Service




SYS-306886 Fixed: In the output of the ipinterface_list_ports CLI command, all iSCSIports might be listed with the Link Up status, even though some ports have noconnectivity.

Severity: Low


Change log 19

Fixes and features of earlier versionsIBM FlashSystem A9000 version 12.3.2.a includes all the features and fixes that were provided inprevious 12.0.x, 12.1.x, 12.2.x, 12.3.0.x, 12.3.1.x, and 12.3.2 versions.

To obtain information regarding previously introduced FlashSystem A9000 features or issues that wereresolved in previous versions, see FlashSystem A9000 on IBM Knowledge Center (www.ibm.com/support/knowledgecenter/STJKMM).


https://www.ibm.com/support/knowledgecenter/STJKMM

LimitationsAs opposed to known issues, limitations are functionality restrictions that are part of the predefinedsystem design and capabilities in a particular version.

Synchronous mirroring limitations

Use of synchronous remote mirroring is subject to the following:

• The reported size of data written on the master volume and slave volume are not equal, since zero datawrites are not counted for the slave volume. This is by design and no actual data is lost.

Limitations with IBM SAN Volume Controller

When using IBM FlashSystem A9000 as the back-end storage of IBM SAN Volume Controller, the IBMFlashSystem A9000 system is not aware of user data that is deleted or migrated on the front-end SANVolume Controller. In addition, the IBM FlashSystem A9000 physical capacity usage is not monitored bythe front-end IBM SAN Volume Controller.

As a result, the IBM FlashSystem A9000 system cannot regularly reclaim freed capacity, and over time itmay unexpectedly for the storage administrator run out of physical storage space.

To mitigate this limitation, when using IBM FlashSystem A9000 as a back-end storage of an IBM SANVolume Controller, administrators are strongly advised to:

• Closely monitor the IBM FlashSystem A9000 physical capacity using IBM Hyper-Scale Manager or IBMExtended Command-Line Interface (XCLI) Utility.

• Keep track of IBM FlashSystem A9000 capacity-related events.• Upgrade to software version 8.1 or later of IBM SAN Volume Controller.


Known issuesThis section details the known issues in IBM FlashSystem A9000 version 12.3.2.a, along with possiblesolutions or workarounds (if available).

The following severity levels apply to known issues:

• HIPER – High Impact Pervasive. A critical issue that IBM has either fixed or plans to fix promptly.Requires immediate customer attention or code upgrade.

• High Impact – Potentially irrecoverable error that might impact data or access to data in rare cases orspecific situations/configurations.

• Moderate – Limited functionality issue and/or performance issue with a noticeable effect.• Service – Non-disruptive recoverable error that can be resolved through a workaround.• Low – Low-impact usability issue.

Important:

• The issues listed below apply to version 12.3.2.a or earlier versions. As long as a newer version hasnot yet been released, a newer release notes edition for version 12.3.2.a might be issued to provide amore updated list of known issues and workarounds.

• When a newer version is released for general availability, the release notes of version 12.3.2.a will nolonger be updated. Accordingly, check the release notes of the newer version to learn whether anynewly discovered issues affect version 12.3.2.a or whether the newer version resolves any of theissues listed below.

Ticket ID SeverityAffectedversions Description

SYS-305091 High Impact 12.0.0or later

In rare cases, using the io_pause command might causeloss of access to the storage system.

Note: Starting from version 12.2.1, this CLI command isdisabled until a fix for this issue becomes available.

Workaround: No workaround is currently available.


When the storage system enters an out-of-physical-spacestate and the SYSTEM_OUT_OF_PHYSICAL_SPACE event islogged, freeing up physical space will allow the storagesystem to return to normal operation. However, in rare cases,the storage system might enter the same state again, even ifthere is some free space available.

Workaround: Contact IBM Support.


When an encrypted storage system is powered up, it mayenter the maintenance state due to an issue in the encryptionkey management mechanism.





In rare cases, when using the mirror_delete CLI commandtogether with the force_on_slave=yes parameter on anasynchronous mirroring relation or a Multisite HA DR relation,while the volume is part of an active consistency group (CG),any asynchronous mirror volumes will not be updated, andmiscellaneous management operations might fail and need tobe retried.


SYS-280406 Moderate 12.0.2or later

Upon the creation of a snapshot, the system I/O latency couldincrease, for a duration of up to several minutes.



Performance improvements that were introduced in version12.0.2 cannot be applied on data that was written to thesystem prior to upgrading to version 12.0.2.

Workaround: When experiencing performance issues withdata that was written to the system prior to upgrading toversion 12.0.2, contact IBM Support.


When unmapping a migrated volume (with IBM Hyper-ScaleMobility) or a HyperSwap volume from a cluster, a delay of thehost I/O response might be experienced, ranging from 20 to170 milliseconds.



Using the IBM Hyper-Scale Mobility (volume migration)feature between XIV® Gen3 systems and FlashSystem A9000or A9000R systems is not supported during the hot upgradeof FlashSystem A9000 or A9000R.



When performing a system wipe-out operation and thendisabling the system's data encryption (for example, for thepurpose of moving the system), the system performs severalemergency shutdowns before the encryption disabling iscompleted.

Workaround: Manually restart the system and allow thedecryption process to complete.


In a HyperSwap configuration, attaching a Quorum Witness toa domain is not possible.



IP filtering is not enforced by the IP_ACCESS CLI commandwhen the management ports are assigned with a VLAN ID.




SYS-314708 Moderate 12.0.0 orlater

When using the host_delete CLI command on one of thesecondary system ports designated for a HyperSwap volumeonly the secondary system port is removed and the port onthe primary system remains configured. This can expose thevolume to SCSI reservation conflict, causing unexpectedaccess restrictions until the port is removed.

Workaround: To avoid this issue, be sure to remove the portfrom the primary system before deleting the host, using thehost_remove_port CLI command. If the port was notremoved prior to using the host_delete CLI command,contact IBM support.

SYS-315170 Moderate 12.0.1 orlater

In some cases when using a KeySecure key server, theencrypt_disable CLI command fails to complete and theENCRYPT_UNABLE_TO_UPDATE_KEY_DURING_DEACTIVATE_ON_KEYSERVER event is emitted.

Workaround: If the key already exists, and theENCRYPT_UNABLE_TO_UPDATE_KEY_DURING_DEACTIVATE_ON_KEYSERVER is emitted, go to the Life Cycle propertiesdialog box of the key on the key server, and change the statefrom Pre-Active to Active. Once the key state is Active,repeat the encrypt_disable CLI command.

SYS-279815 Service 12.0.0or later

If a MicroLatency module is pulled out of the flash enclosurewhen the enclosure's internal redundancy state is either'Synching' or 'Degraded', the management GUI indicates thatthe card has a spare, even if no spare is available.

Workaround: Use the flash_card_list CLI command todisplay the correct status of spares.


Some CLI commands might hang when storage pools arebeing cleaned from snapshots.

Workaround: In such a case, wait until the command iscarried out.


Data migration over Fibre Channel (FC) does not work if thenumber of LUNs per host exceeds 255.

Workaround: To resolve this issue, use 255 or less LUNs perhost.


Enabling encryption of a flash enclosure that contains a failedflash canister could lead to partial encryption of the flashenclosure, or to complete encryption failure.

Workaround: To avoid this issue, before enabling encryption,verify that no flash enclosure contains a failed canister.Otherwise, contact IBM Support.

Known issues 27



When setting up LDAP authentication, entering the storagesystem password is required, but this requirement is notenforced. This could lead to LDAP authentication failure if thepassword is not provided.

Workaround: To avoid this issue, always make sure toprovide the storage system password in order to allow accessto the storage system.


An attempt to deactivate a Quorum Witness might render theQuorum Witness unresponsive, and remain in the Deactivatingstate without timing out (see also SYS-285120 below).

Workaround: To resolve this issue, proceed as follows in IBMHyper-Scale Manager:

1. Remove the current Quorum Witness configuration.

This action disassociates the Quorum Witness from theconnected system(s).

2. Define a new Quorum Witness and make sure that thecorrect port is used.

3. Activate the newly defined Quorum Witness.4. Connect the system(s), that were previously using the

removed Quorum Witness, to the newly defined QuorumWitness.


When connecting a system to a Quorum Witness, the QuorumWitness might become unresponsive, and remain in theActivating state without timing out.

Workaround: To resolve this issue, proceed as follows in IBMHyper-Scale Manager:

1. Deactivate the Quorum Witness. Note that the QuorumWitness state changes to Deactivating and remainsDeactivating without timing out (see also SYS-284512above).

2. Remove the current Quorum Witness configuration.

This action disassociates the Quorum Witness from thesystem(s).

3. Define a new Quorum Witness and make sure that thecorrect port is used.

4. Activate the newly defined Quorum Witness.5. Connect the system(s), that were previously using the

removed Quorum Witness, to the newly defined QuorumWitness.


When an IBM Support technician is removing a canister fromthe flash enclosure for maintenance purposes, multipleevents ofPOD_IB_LINK_DETECTION_LINK_PERSISTENTLY_DISCONNECTED might be unnecessarily emitted.

These events can be safely ignored.




When the CLI command reservation_key_list is appliedto the entire system, the command output displays themaximum of 512 keys, even if the factual number of keys isgreater. However, when applied to a volume,reservation_key_list outputs the entire key list.

Workaround: Apply the command reservation_key_listper volume.


In rare cases, the ha_create command might fail.

Workaround: Retry the operation.


If there are more than 200 volumes in a HyperSwap relationand a failover takes place, some of theHA_AUTOMATIC_FAILOVER_SUCCESFUL events might belost. This does not affect the actual failover.



When removing a target port and adding it back within lessthan 3 seconds, the high availability state for HyperSwapvolumes is insufficient, and aTARGET_CONNECTIVITY_HA_INSUFFICIENT event isissued.


SYS-287533 Service 12.1.0 orlater

Previously listed as SYS-310649.

In rare cases, when adding a volume to a consistency group(CG) with the cg_add_vol command, the operation might failwith the event MIRROR_LAST_SYNC_TIMES_DIFFERrecorded.

Workaround: To avoid this issue, retry the cg_add_volcommand after the mirroring synchronization is completed.


When using HyperSwap, the HA_MASTER_UNAVAILABLE andHA_MASTER_AVAILABLE system events are not logged for allvolumes and consistency groups after a system rebootfollowed by disconnection from the peer system. As a result,incorrect values are shown when using the ha_listcommand as long as the disconnection continues.

Workaround: Wait until the high availability connection to thepeer system is reestablished. The correct information willthen be displayed.


When using IBM Hyper-Scale Mobility and aborting (witholvm_abort) a migration process that is currently in Proxystate, the remote volume remains in locked read-only state.

Workaround: Use the vol_unlock command to unlock thevolume state.

Known issues 29



Manually created snapshots that have a reserved name prefixprevent the automatic creation of additional snapshots.

Workaround: Delete and do not manually create snapshotsthat have a reserved name prefix.


The switch_mgmt_ip_list CLI command does not workwhen using the additional switch argument for displayingthe management IP address of a specific InfiniBand switch.

Workaround: Use the switch_mgmt_ip_list commandwithout the switch argument. This will display themanagement IP addresses of all InfiniBand switches.


In some cases of desynchronization in the phase-out processof a grid element, the node_failed and taken_over eventscould be recorded. This does not impact any critical systemoperation.



In rare cases, the Fibre Channel (FC) driver might crash andthen immediately be restarted automatically. In such a case,the FC_LINK_IS_NOW_UP event is logged.



In rare cases, theTARGET_CONNECTION_HA_INSUFFICIENT event appears,followed by the TARGET_CONNECTION_HA_SUFFICIENTevent after a few seconds. This behavior has no actual impact.



When using HyperSwap and a volume fails to besynchronized, theVOLUME_IS_NOT_CONSISTENT_OLVM_DESTINATION eventis logged instead of theVOLUME_IS_NOT_CONSISTENT_HA_DESTINATION event.


SYS-276870 Low 12.0.0or later

When a grid controller is replaced, or whenever the system isundergoing a software initiation process, data reductionsaving statistics could be temporarily inaccurate. Thestatistics accuracy is regained as data is being accessed andprocessed again.

This issue has a noticeable effect only when 1 TB or less hasbeen written to the system.



In rare cases, the process of enabling encryption may notcomplete successfully due to a timeout. If this occurs, thesystem emits the ENCRYPT_ENABLE_NOT_COMPLETED eventwith all the relevant details.

Workaround: Retry activating encryption.




By design, an attempt to set up IBM Hyper-Scale Mobility,when a volume with the same name as the source volumealready exists at the destination system, fails due to an illegalvolume name. However, the emitted return code(REMOTE_VOLUME_NOT_APPLICABLE_FOR_OLVM) provides awrong reason for the failure.



In the output of the ipinterface_list_ports CLIcommand, all iSCSI ports might be listed with the Link Upstatus, even though some ports have no connectivity.



When iSCSI connectivity is used with a host, theHOST_NO_MULTIPATH_ONLY_ONE_PORT event might belogged, even though the host is connected through more thanone iSCSI path.



When a Multi-site HA DR relationship relation is established, ittakes a few seconds for the Standby connectivity status to beupdated. During this short period, no volume can be added toa consistency group.

Workaround: Repeat the CLI command or GUI operation.

SYS-315110 Low 12.0.0 orlater

The ipinterface_run_arp and ipinterface_list_ipsCLI commands do not support iSCSI (IP-based) interfacequeries.

Workaround: Use the ipinterface_list CLI command foriSCSI interface queries.

Known issues 31

Known interoperability issuesThis section describes known issues or limitations that could arise when using IBM FlashSystem A9000 inconjunction with other components in the production environment, such as hardware switches, host busadapters (HBAs), other IBM products, or different software platforms such as operating systems,clustering solutions, virtual machine servers, multipathing solutions, and other third-party components.



Failover of a Windows Server 2008 or 2008 R2 cluster groupresults in a stop error on the new active node. This could occurwhen using these Windows Server versions with HyperSwapvolumes. No hotfix is currently available.

Workaround: Refer to IBM Support guidelines for WindowsServer 2008 and 2008 R2 as described in IBM Technote#S1010299.


The HyperSwap feature is not compatible with VMware ESXi 6.0Update 2 or earlier.

Workaround: Use ESXi 6.0 Update 3 or later.


Veritas Dynamic Multi-Pathing (DMP) in any configuration doesnot support HyperSwap volumes.



http://www.ibm.com/support/docview.wss?uid=ssg1S1010299

http://www.ibm.com/support/docview.wss?uid=ssg1S1010299

Related information and publicationsYou can find additional information and publications related to IBM FlashSystem A9000 on the followinginformation sources.

• IBM Flash Storage marketing website (ibm.com/systems/storage/flash)• IBM FlashSystem A9000 on IBM Knowledge Center (ibm.com/support/knowledgecenter/STJKMM)• IBM FlashSystem A9000R on IBM Knowledge Center (ibm.com/support/knowledgecenter/STJKN5)• IBM Hyper-Scale Manager on IBM Knowledge Center (ibm.com/support/knowledgecenter/SSUMNQ)• IBM Storage Redbooks® website (redbooks.ibm.com/portals/storage)


http://www.ibm.com/systems/storage/flash/


http://www.ibm.com/support/knowledgecenter/STJKN5

http://www.ibm.com/support/knowledgecenter/SSUMNQ

http://www.redbooks.ibm.com/portals/storage

Getting information, help, and service

If you need help, service, technical assistance, or want more information about IBM products, you canfind various sources to assist you. You can view the following websites to get information about IBMproducts and services and to find the latest technical information and support.

• IBM website (ibm.com®)• IBM Support Portal website (ibm.com/storage/support)• IBM Directory of Worldwide Contacts website (ibm.com/planetwide)• IBM service requests and PMRs (ibm.com/support/servicerequest/Home.action)

Use the Directory of Worldwide Contacts to find the appropriate phone number for initiating voice callsupport. Voice calls arrive to Level 1 or Front Line Support.


http://www.ibm.com

http://www.ibm.com/storage/support

http://www.ibm.com/planetwide

http://www.ibm.com/support/servicerequest/Home.action

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