Deciding if you want to use shadow copies
You can reduce the time it takes to forward recover a VSAM file by creating a shadow copy of it.
With a shadow copy, you:
- Create a copy of the VSAM sphere.
- Regularly run a CICS® VR shadow forward recovery job to update that copy with all the log entries up to the current time.
If the shadow forward recovery job is run often, the shadow copy of the VSAM sphere is kept up-to-date. If the VSAM sphere is damaged, only a few updates need to be made to the shadow copy to return it to the same state as the original VSAM sphere.
Shadow forward recovery is intended for users who want to maintain a copy of critical data sets to reduce the forward recovery time.
Shadow copies are also useful at remote recovery sites when using products such as Remote Recovery Data Facility (RRDF).
The following topics are discussed in this section:
- Preparing for shadow forward recovery
- Replacing the original sphere with a shadow copy