IT10784: SOMETIMES SERVER DOESN'T RAISE OUT OF MEMORY MESSAGE WHEN NEW VIRTUAL SEGMENT ALLOCATION EXCEEDS SHMTOTAL

APAR status

• Closed as fixed if next.

Error description

• As shown in the example below sometimes the server allocates a
  new virtual segment though SHMTOTAL is exceeded but other times
  it does not.
  
  Example 1 no OOM message:
  
  15:32:57  Dynamically allocated new virtual shared memory
  segment (size 32768KB)
  15:32:57  Memory sizes:resident:6564 KB, virtual:247316 KB,
  SHMTOTAL:300000 KB
  15:32:58  Dynamically allocated new virtual shared memory
  segment (size 32768KB)
  15:32:58  Memory sizes:resident:6564 KB, virtual:280084 KB,
  SHMTOTAL:300000 KB
  15:33:00  Dynamically allocated new virtual shared memory
  segment (size 32768KB)    << Should have raised OOM message in
  the log and fail to allocate segment
  15:33:00  Memory sizes:resident:6564 KB, virtual:312852 KB,
  SHMTOTAL:300000 KB
  
  Example 2 is a proper OOM message raised:
  
  16:21:02  Dynamically allocated new virtual shared memory
  segment (size 32768KB)
  16:21:02  Memory sizes:resident:6564 KB, virtual:247316 KB,
  SHMTOTAL:275000 KB
  16:21:03  Dynamically allocated new virtual shared memory
  segment (size 32768KB)
  16:21:03  Memory sizes:resident:6564 KB, virtual:280084 KB,
  SHMTOTAL:275000 KB
  16:21:05  Size of resident + virtual segments 6564KB + 226304KB
  > 275000KB
  16:21:05          total allowed by configuration parameter
  SHMTOTAL
  16:21:05  out of virtual shared memory
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * admins checking for outofmemory messages and alarms          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to 12.10.xC6                                         *
  ****************************************************************
  

Problem conclusion

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

Applicable component levels

• RA10 PSN

     UP

• RA10 PSY

     UP

• RB10 PSN

     UP

• RB10 PSY

     UP

• RC10 PSN

     UP

• RC10 PSY

     UP