Data Backup and Recovery

no consistend online logs (Oracle 11.2)



i`m using NetApp SnapCreator (3.5) to make snapshots of oracle (11.2) databases. I recongnized, when a SnapShot is done (incl. begin and end backup) during a peak time of the database, the online logs are not consistend, only the datafiles.

Is this a normal behaviour or am i doing something wrong?





The online logs aren't part of a hot backup. Recovering a hot backup requires two things:

1) An image of the datafiles while in hot backup mode.

2) Every archive log generated while in hot backup mode.

When SC completes a hot backup, it will force a log archival.

Most of the time if you need to recover the required archive logs are already present in the archive log location. You don't generally need to recover anything. You just restore the datafiles from the hot backup snapshot and replay archive logs to the desired point in time.

With SC, you need to be careful about how you restore. If you recover the entire snapshot where the datafiles were in hot backup mode and that volume also contains those archive logs, you will have erased the archive logs required to bring the datafiles online.

There are multiple options. Some users put the archive logs on a separate volume and schedule a snapshot within ONTAP. Other customers will leverage the META_DATA_VOLUME option to get a separate snapshot of the archive logs after the hot backup completes.

  • The meta data volume needs to be defined via META_DATA_VOLUME and also in the regular VOLUMES parameter.
  • Snapshots are performed on the VOLUMES (without the META_DATA_VOLUME) and after the unquiesce of the database, then the META_DATA_VOLUME get its snapshot.