Recovering the compression dictionary data set without bringing down a Db2 data sharing group

If the compression dictionary data set (CDDS) becomes logically damaged, you need to recover or rebuild it.

About this task

An implementation of the GDPS® Continuous Availability with zero data loss (GDPS Continuous Availability with zero data loss) solution uses a CDDS for the source data sharing group. Before you can recover a CDDS, the CDDS must be closed and deallocated. You can close and deallocate the CDDS without stopping the Db2 data sharing group by issuing the -STOP CDDS command. After you recover the CDDS, you can allocate and open the CDDS by issuing the -START CDDS command.

To recover or rebuild a CDDS, follow these steps in the source data sharing group:

1. Issue the -STOP CDDS command to direct all members of the data sharing group to close and deallocate the CDDS.
2. Issue the DFSMSdss RESTORE command to restore the CDDS from the latest backup copy.

   If you do not have a backup copy, delete and redefine the CDDS. See Modifying Db2 for the GDPS Continuous Availability with zero data loss solution for an example of the CDDS definition.

3. Issue the -START CDDS command to direct all members of the data sharing group to allocate and open the CDDS.
4. Run REORG TABLESPACE with the INITCDDS option to repopulate the CDDS.

   You can specify the SEARCHTIME option with the INITCDDS option to allow REORG to populate the CDDS with an earlier dictionary than the dictionary that currently resides in the target table space.