IT38689: LOOPING "WARNING: MT_AIO_WAIT: ERRNO == EINVAL OPERATION = 3" MESSAGE WHEN ADDING RAW CHUNK WHEN SIZE+OFFSET IS TOO LARGE

APAR status

• Closed as program error.

Error description

• When adding a raw chunk and specifying a size+offset that is
  larger than the raw device, it is considered expected behavior
  to see one iteration of this message in the onconfig file:
  
  WARNING: mt_aio_wait: errno == EINVAL operation = 3
  Assert Warning: WARNING: mt_aio_wait: errno == EINVAL
  IBM Informix Dynamic Server Version 12.10.FC14
  Who: Session(<sessionid>, informix@host, ...)
          Thread(<threadid>, onspace, ...)
          File: aio_gskit.c Line: 3235
  See Also: /path/af....
  WARNING: mt_aio_wait: errno == EINVAL
  
  However, in certain configurations, the chunk addition can loop
  for an extended period of time with many of the above messages
  in MSGLOG.  The stack for this scenario resembles:
  
  (from 12.10.FC14 on Linux)
  0x0000000001410459 (oninit) afstack
  0x0000000001413431 (oninit) afhandler
  0x0000000001413b52 (oninit) afwarn_interface
  0x00000000013f19c7 (oninit) mt_aio_wait
  0x00000000013f42d2 (oninit) mt_aio_start
  0x00000000013f46dd (oninit) mt_aio_read
  0x0000000000e767ec (oninit) verchunkx
  0x0000000000e6933b (oninit) chkstat_be
  0x0000000000e69964 (oninit) chkfields
  0x0000000000e6bdc2 (oninit) add_chunk
  0x0000000000e6fa0f (oninit) onspace
  0x000000000154290b (oninit) spawn_thread
  0x0000000001401c70 (oninit) th_init_initgls
  0x0000000001448997 (oninit) startup
  
  
  It seems as if this only impacts 12.10.xC13+ and 14.10.xC2+.
  

Local fix

• Possible workarounds:
  1.  Move socket poll threads to NET VPs.
  2.  Set onconfig parameter DIRECT_IO to 1.  This may still
  produce more than one error.
  3.  Note the value of AFWARN from onstat -g ras (likely 0x401),
  run onmode -wm AFWARN=0x800, add the raw chunk(s), then set
  AFWARN
  back to the original value with onmode -wm AFWARN=0x401.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC16 and 14.10.xC8.  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 12.10.xC16 or 14.10.xC8.          *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 12.10.xC16 and 14.10.xC8.
  

Temporary fix

Comments

APAR Information

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

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

Fix information

• Fixed component name

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels