Falling back in a data sharing environment

If you need to fall back to Db2 12, you can fall back one member of the data sharing group at a time. Other members can continue to run while one member is falling back.

Before you begin

Important: Do not issue the ACTIVATE command or run job DSNTIJAF for activation of Db2 13 until you are certain that the subsystem or data sharing group can proceed on Db2 13, without the possibility of falling back to or coexistence with Db2 12. In data sharing, the ACTIVATE command has group scope. Fallback and coexistence become impossible with the successful activation of function level 500 or higher.

If all members have already been migrated to the new release, and you fall back one member at a time, the group is running in coexistence mode after the first member falls back.

Procedure

To fall back to Db2 12:

  1. Stop Db2 on the member that is falling back or stop Db2 on all members if you are falling back all members at once.
  2. Run job DSNTIJFV to reactivate Db2 12 for that member or for all members.
  3. Reconnect TSO, IMS, CICS® to Db2 12.
  4. Start Db2 12:
    1. Enter the command START DB2:
      1. Check for indoubt units of recovery.
      2. Check for outstanding restrictive states.
  5. Verify Db2 12.
  6. Repeat steps 1 through 5 for each member (or all members) of the data sharing group.