requested number of KAIO events (819200) exceeds limit (204800). using 204800

IT30983: ON LINUX X86_64, SERVER CAN ASSERT INITIALIZING KAIO WITH -22 EINVAL FROM IO_QUEUE_INIT

APAR status

• Closed as program error.

   

Error description

• Consider this entry in /etc/sysctl.conf on linux x86_64:
  
      fs.aio-max-nr = 6,000,000
  
  Propagate the setting:
  
      sysctl -p /etc/sysctl.conf
  
  If you set the env variable KAIOON=500000, the server will fail
  with following when you try to bring it online:
  
  There appears to be an undoc'ed hard-coded OS value that is
  limiting the server despite KAIOON being less than
  fs.aio-max-nr:
  
      11:58:23  requested number of KAIO events (5000000) exceeds
  limit (3000000). using 3000000.
      11:58:23  Assert Failed: initializing KAIO failed
      11:58:23  IBM Informix Dynamic Server Version 12.10.FC7
      11:58:23   Who: Session(1, login@host, 0, (nil))
                      Thread(137, kaio, 0, 1)
                      File: kaioapi.c Line: 298
      11:58:23   Results: io_queue_init(3000000) failed returning
  -22, errno = 0
      11:58:23  stack trace for pid 21255 written to
  /tmp/af.471dbbe
      11:58:23   See Also: /tmp/af.471dbbe
      11:58:27  initializing KAIO failed
      11:58:28  io_queue_init(3000000) failed returning -22, errno
  = 0
      11:58:28  Assert Failed: kaiothread() ERROR
  
  A similar error can be observed for a lower value of KAIOON
  (1500000):
  
      12:18:23  Assert Failed: initializing KAIO failed
      12:18:23  IBM Informix Dynamic Server Version 12.10.FC7
      12:18:23   Who: Session(1, login@host, 0, (nil))
                      Thread(113, kaio, 0, 1)
                      File: kaioapi.c Line: 298
      12:18:23   Results: io_queue_init(1500000) failed returning
  -22, errno = 0
      12:18:23  stack trace for pid 22650 written to
  /tmp/af.459e06e
      12:18:23   See Also: /tmp/af.459e06e
      12:18:25  initializing KAIO failed
      12:18:25  io_queue_init(1500000) failed returning -22, errno
  = 0
      12:18:25  Assert Failed: kaiothread() ERROR
  
  For both cases the stack of the asserting thread is:
  
      12:18:23  Stack for thread: 113 kaio
  
       base: 0x000000004827f000
        len: 69632
         pc: 0x00000000013cf857
        tos: 0x000000004828f090
      state: running
         vp: 1
  
      0x00000000013cf857 (oninit) afstack
      0x00000000013d29ee (oninit) afhandler
      0x00000000013d2e62 (oninit) affail_interface
      0x0000000001427e21 (oninit) _aioinit
      0x00000000013c1460 (oninit) kaiothread
      0x0000000001428327 (oninit) startup
  

   

Local fix

•  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC14 and 14.10.xC4.  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Update to Informix Server 12.10.xC14 or 14.10.xC4.           *
  ****************************************************************
  

   

Problem conclusion

• Fixed in Informix Server 12.10.xC14 and 14.10.xC4.
  

   

Temporary fix

•  

Comments

•  

APAR Information

• APAR number

  IT30983

• Reported component name

  INFORMIX SERVER

• Reported component ID

  5725A3900

• Reported release

  C10

• Status

  CLOSED PER

• ON

  NoPE

• HYPER

  NoHIPER

• Special Attention

  NoSpecatt / Xsystem

• Submitted date

  2019-11-18

• Closed date

  2020-06-08

• Last modified date

  2020-06-08

• 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