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Question

Copycluster and backup consistency

  • March 30, 2023
  • 3 replies
  • 7 views

bmurrell
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It's unclear from the documentation at what point a copycluster or backup is consistent.
For a backup, the documentation states "This type of backup provides a consistent image of the database at the time the backup occurred.", but if a backup takes 1.5 hours, is that the start or end of the backup or copycluster ?
In some databases (Oracle) it's at the end, and others (Informix) it's at the start.
Does vbr put a hold on file deletions while it's running in order that all files that are present at the start are still present at the end and are not missed while copycluster'ing or backing up ?

3 replies

Bryan_H
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  • Participating Frequently
  • March 30, 2023

The backup process snapshots the catalog at the start of the backup transaction, so that is the point of consistency.


bmurrell
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  • Author
  • Participating Frequently
  • March 30, 2023

Thanks Bryan, and for the last question, does vbr put a hold on file deletions while it's running in order that all files that are present at the start are still present at the end and are not missed while copycluster'ing or backing up ?


Bryan_H
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  • Participating Frequently
  • April 1, 2023

There is transaction isolation during vbr: Internal task "Database Snapshot" holds a catalog lock while backup runs, which would block deletes during backup. Deletes and purges would not commit until after backup in this case.