Changing block size for the OLDS

You can change the space, location, or block size of your OLDS or reallocate an OLDS on the same volume and with the same space.

Procedure

  1. Shut down IMS.
  2. Archive all OLDSs.
  3. Delete PRIOLDS and SECOLDS records from the RECON data sets by using the DELETE.LOG command of the Data Base Recovery Control utility program (DSPURX00).
  4. If the BLKSIZE= parameter is defined in the LOGGER section of the DFSDFxxx PROCLIB member, it overrides any other value associated with any OLDS. Change the BLKSIZE= parameter in the LOGGER to the new block size, if it is defined. Else, scratch all OLDSs and reallocate them with the new BLKSIZE.
  5. Verify WADS space allocation.
  6. Restart IMS (from SLDS).
Changing the OLDS block size can affect the space required for the IMS write-ahead data set (WADS) . For example, if you have your WADS sized to hold a hundred 22K buffers, and you increase the OLDS block size to 24K, you might need to increase the size of the WADS if you want it to be able to hold a hundred of the larger 24K buffers. If you reallocate the WADS, make sure that you restart IMS by using the /NRE FORMAT WA or /NRE FORMAT ALL command.