Which database files does SnapCenter for Oracle create Snapshots on ?
Applies to
- SnapCenter Plug-in for Oracle (SCO)
- Oracle Data Guard
Answer
- Oracle database table space files are the primary snapshot target on ONTAP volumes for backups, this snapshot gets a _1 name extension.
- Oracle archive log backups, are the secondary target for Snapshot backups with _0 extension on the snapshot name, except when (Active) DataGuard is used
- Oracle redo logs are only targeted for a Snapshot when Data Guard is in use
- Oracle control files are copied to the table space storage before the main snapshot is created, except in an ASM RAC environment (*)
This means that control files, temp files and, for Data Guard (active) standby databases, the archive logs, can all be on local storage.
For non-Data Guard (i.e. "normal" databases), the redo logs can also be on local storage.
Additional Information
(*) See also "Why doesn't SCO create snapshots on the storage for control files ?"
Data Guard (active) standby database backups are also documented under "Types for Oracle backups supported..."
Note: non-active Data Guard standby databases can only be backed up with the Offline/mount option, and active ones only with Online, no logs.
To identify which LUN is which multipath mapper device, it can help to install the Host Utilities for Linux (e.g. 7.1), and use "sanlun lun show -p
" before providing ASM names to the disks for usage by a RAC database (for example). Mixing volumes between Archive log and Database paths may cause both _0 (database) and _1 (archive logs) snapshots to appear on the same volume.