IV97772: UNDETECTED DATA LOSS AFTER STORAGE ERRORS WITH CERTAIN ADAPTERS

APAR status

• Closed as program error.

Error description

• **************************************************************
  * USERS AFFECTED:
  * Systems running the AIX 7100-03 Technology Level
  * with devices.pciex.df1060e214103404.com at or below
  * the 7.1.3.49 level,
  * devices.fcp.disk.rte at or below the
  * 7.1.3.49 level,
  * devices.pci.df1000f7.com at or below the
  * 7.1.3.49 level, and
  * devices.pci.77102224.com at or below the
  * 7.1.3.50 level.
    **************************************************************
  * ERROR DESCRIPTION:
  * On an AIX or VIOS LPAR using a physical Fibre Channel
  * adapter or Virtual Fibre Channel (NPIV) adapter, with
  * certain storage devices (see below), if communication
  * between the LPAR and the storage device is severed and
  * there are multiple writes to the same block happening at
  * that time, after the path fails, the driver may retry I/Os
  * down an alternate path too quickly and data may be written
  * to the device in a different order than it is completed to
  * the application, possibly resulting in undetected data loss.
  *
  * We have seen this, for example, when testing a link drop by
  * pulling FC cables between LPARs and storage.
  *
  * We have seen this issue occur when testing the following
  * storage devices:
  * - IBM Flash Systems
  * - IBM San Volume Controller (SVC) with caching turned off
  *   for the volume
  * - IBM Storwize family products with caching turned off
  * for the volume
  *
  * This issue CANNOT occur with the following storage devices:
  * - IBM DS8000 series
  * - IBM San Volume Controller (SVC) with caching turned on
  *   for the volume
  * - IBM Storwize family products with caching turned on
  * for the volume
  * - IBM XIV family
  * - EMC Symmetrix family
  *
  * Storage devices not specifically mentioned above should be
  * assumed to be exposed to this problem.
  *
  * This issue also cannot occur when reserve_policy for the
  * disks is set to single_path.
    **************************************************************
  * RECOMMENDATION:
  * An interim fix is available from either
  * ftp://aix.software.ibm.com/aix/ifixes/iv97772/
  * https://aix.software.ibm.com/aix/ifixes/iv97772/
  * Installation of the ifix requires a reboot.
    **************************************************************
  

Local fix

Problem summary

• IO errors
  

Problem conclusion

• Addressed errors
  

Temporary fix

•   *********
    * HIPER *
    *********
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IV96603

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels