IT34770: INFORMIX INSTANCE RUNNING ON UBUNTU 20.04 FAILS TO START AFTER ADDING A SHARED MEMORY CONNECTION

APAR status

• Closed as documentation error.

Error description

• Adding the following shared memory connection to an instance
  previously configured and running successfully with just network
  connections:
  
  ol_informix1410_shm     onipcshm        jj-ubuntu2004
  dummy_shm
  
  The startup fails as below:
  
  Assert Failed: shm_be.c, line 3452, thread 13, errno=13, could
  not open shm file.
  IBM Informix Dynamic Server Version 14.10.FC4W1DE
  Who: Session(7, informix@, 0, (nil))
          Thread(13, sm_listen, 0, 1)
           File: neterrb.c Line: 530
  stack trace for pid 2061 written to
  /products/14.10.FC4W1/tmp/af.3f54d3d
  See Also: /products/14.10.FC4W1/tmp/af.3f54d3d
  Thread ID 13 will NOT be suspended because it is deemed too
  critical to the server.
  
  Root cause is that Ubuntu 20.04 has the following kernel
  parameter with default value:
  
  sysctl -a | grep fs.protected_regular
  fs.protected_regular = 2
  

Local fix

• Setting fs.protected_regular to 0 (not 1 or 2) and the instance
  starts successfully
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 14.10.xC6.                 *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 14.10.xC6 (when available).       *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 14.10.xC6.
  

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