Encrypting the write-ahead data sets (WADS)

To encrypt WADS, define WADS as extended format and associate a key label with it. For XRF and FDBR systems, APAR PI84947 must be applied to both systems before enabling WADS encryption.

You can encrypt WADS while IMS remains up or across a restart. IMS can use up to 10 WADS, which are numbered 0 - 9.

When you are migrating from non-encrypted WADS to encrypted WADS, recycle IMS before this migration if the following conditions are met:
  • Different data set names are used for encrypted and non-encrypted WADS.
  • Dynamic allocation (DFSMDA member) is not used for the WADS data set names. That is, there are DD statements in the control region JCL for the WADS.
This is because the online control region will have the WADS allocated and you will be unable to delete the WADS while IMS remains up.

Migration procedure across a restart

  1. Ensure that IMS comes down cleanly.
  2. Delete all WADS.
  3. Define all WADS as extended format and with key labels specified.
  4. Optional: If you use different data set names for the encrypted WADS, update the MDA members or change the DD statements in the control region JCL.
  5. Cold start IMS by issuing the /NRESTART command with FMT WA or FMT ALL specified.

Migration procedure when IMS remains up

  1. Issue the /DISPLAY OLDS command to see which WADS are in use.
  2. Issue the /STOP WADS command for the WADS that are not in use.
  3. Delete all of the WADS that are stopped and define them as extended format and with key labels specified.
  4. Optional: If you use different data set names for the encrypted WADS, update the MDA members.
  5. Issue the /START WADS command for each WADS that was deleted and defined. WADS are formatted as part of the /START WADS command processing.
  6. Issue the /SWITCH WADS command.
  7. Issue the /STOP WADS command for the WADS that are switched from. If you use dual WADS, issue this command for each WADS that is switched from.
  8. Delete the WADS that are switched from and define them as extended format and with key labels specified.
  9. Optional: If you use different data set names for the encrypted WADS, update the MDA members.
  10. Issue the /START WADS command for the WADS that were deleted and defined.