Problem: storage shortage in the SCA

In a data sharing environment, you might encounter a problem that is caused by a storage shortage in the SCA.

Symptoms

The following message appears: 
DSN7505A -DB1A csect-name THERE IS A SHORTAGE OF FREE STORAGE
          IN SCA STRUCTURE sca-structure-name.
If you do not do anything to reclaim space, such as recovering pages from the logical page list, the following message appears when the SCA is 90% full: 
DSN7512A -DB1A csect-name THERE IS A CRITICAL SHORTAGE OF
          FREE STORAGE IN SCA STRUCTURE sca-structure-name.

System action

Some critical functions that cannot be completed can cause one or more members of the group to come down with reason code 00F70609.

System programmer action

Perform the following steps:
  1. Reclaim space in the SCA by removing exception conditions. You can issue START DATABASE commands with the SPACENAM option, or use the RECOVER utility to remove pages from the logical page list.
  2. Restart any failed members.

If these actions do not free up enough space, or if this problem continues to occur, you have the following options, depending on what level of z/OS® and coupling facility you have.

  • If both of the following conditions are true:
    • The SCA is allocated in a coupling facility with a CFLEVEL greater than 0.
    • The currently allocated size of the SCA is less than the maximum structure size as defined by the SIZE parameter of the CFRM policy.
    You can enter the following command to increase the size of the SCA: 
    SETXCF START,ALTER,STRNAME=DSNDB0A_SCA,SIZE=newsize

    This example assumes that the group name is DSNDB0A, and that newsize is less than or equal to the maximum size defined in the CFRM policy for the SCA structure.

  • If any of the following conditions are true:
    • The SCA is allocated in a coupling facility with CFLEVEL=0.
    • The allocated size of the structure is already at the maximum size defined by the SIZE parameter in the CFRM policy.
    Then you must:
    1. Increase the storage for the SCA in the CFRM policy SIZE parameter.
    2. Use the z/OS command SETXCF START,POLICY to start the updated policy.
    3. Use the following z/OS command to rebuild the structure: 
      SETXCF START,REBUILD,STRNAME=DSNDB0A_SCA
  • If all members are down, and you cannot increase the size of the SCA, you must do the following:
    1. Delete the SCA structure by using the following command: 
      SETXCF FORCE,STRUCTURE,STRNAME=DSNDB0A_SCA
    2. Increase the size of the SCA in the CFRM policy.
    3. Restart Db2 to rebuild the SCA using group restart.