Using the IBM FlashCopy Consistency Group feature to backup IDMS databases
Article ID: 25723
Updated On:
Products
Issue/Introduction
We are using IBM DS6800 devices and the FlashCopy Consistency Group option to backup IDMS databases while the CV region is active. FlashCopy consistency groups ensure data consistency across multiple volumes by putting dependant volumes in an extended long busy state and then performing the backup. This is supposed to guarantee integrity of the data in the dependant volumes. Will this type of backup also guarantee the integrity of an IDMS database?
Environment
Release: All supported releases.
Resolution
This type of backup will not guarantee the integrity of the IDMS database if the backups are taken while IDMS is updating the database. Flashcopy consistency groups can only guarantee integrity at the physical level, not the logical database level. It does not know anything about IDMS transactions, whether the data is committed or not or if data is still in the buffers.
This type of backup is the same as performing a hot backup so the procedure for performing a hot backup needs to be followed. A restore of the database with this type of backup involves running ROLLBACK and/or ROLLFORWARD after the restore just like recovering from a hot backup.
To make the restore procedure much simpler, one option is to perform a quiesced backup, where no updates are done while the area is being backed up.
Additional Information
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