IZ66754: ACTIVE/PASSIVE PCM CONTROLLER HCHECK SUPPORT APPLIES TO AIX 5300-09

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• For active/passive storage device, such as DS3K, DS4K, or DS5K
  if complete access is lost to the storage device, then it
  may take greater than 5 minutes to fail I/O.
  

Local fix

Problem summary

• For active/passive storage device, such as DS3K, DS4K, or DS5K
  if complete access is lost to the storage device, then it
  may take greater than 5 minutes to fail I/O.
  

Problem conclusion

• This feature is for Active/Passive storage devices, which
  are running with the AIX Default A/P PCM.  This includes
  DS3K, DS4K, and DS5K family of devices.
  
  Added feature which health checks controllers when an enabled
  path becomes unavailable due to transport problems.  By
  default this feature is DISABLED.  To enabled this feature
  set the following ODM attributes for the active/passive
  storage device.  Enabling this feature, results in faster
  I/O failure times.
  
  "cntl_hcheck_int" and "cntl_delay_time"
  NOTE: Setting either value to "0" disables this feature.
  
  cntl_delay_time:
  is the amount of time in seconds the storage device's
  controller(s) will be health checked after a transport
  failure.  At the end of this period, if no paths are detected
  as good, then all pending and sebsequent I/O to the device
  will be failed, until the device health checker detects
  a failed path has returned.
  
  cntl_hcheck_int:
  The first controller health check will only be issued after
  a storage fabric transport failure had been detected.
  cntl_hcheck_int is the amount of time in seconds, which
  the next controller health check command will be issued.
  This value must be less than the cntl_delay_time (unless
  set to "0", disabled).
  
  If you wish to allow the storage device 30 seconds to
  come back on the fabric (after leaving the fabric),
  then you can set cntl_delay_time=30 and cntl_hcheck_int=2.
  The device, /dev/hdisk#, must not be in use, when setting
  the ODM values (or the chdev "-P" option must be used,
  which requires a reboot).
  
  CAUTION: There are cases where the storage device may
  reboot both of the controllers and become inaccessible
  for a period of time. If the controller health check
  sequence is enabled, then this may result in an I/O failure.
  It is recommended to to make sure you have an mirrored volume
  to failover to, if you are running with controller health
  check enabled
  (especially with under 60 second cntl_delay_time).
  

Temporary fix

Comments

• 5300-09 - use AIX APAR IZ66754
  5300-10 - use AIX APAR IZ69293
  5300-11 - use AIX APAR IZ65626
  6100-04 - use AIX APAR IZ65627
  

APAR Information

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

  IZ62883

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

  U834235

Fix information

• Fixed component name

  AIX 5.3

• Fixed component ID

  5765G0300

Applicable component levels

• R530 PSY U834235

     UP10/03/23 I 1000