Setting up Volumes for Instant Snapshots
This chapter describes how to make volumes ready for instant snapshot creation. These may be volumes that you want to back up, or that you want to use for decision support or reporting.
If a snapshot volume is to be used on the same host, and will not be moved to another host for off-host processing, you can use space-optimized instant snapshots rather than full-sized instant snapshots. Depending on the application, space-optimized snapshots typically require 10% of the disk space that is required for full-sized instant snapshots.
For more information about administering instant snapshots and FastResync, see the VERITAS Volume Manager Administrator's Guide.
The following table summarizes which volumes require the creation of snapshot mirrors for backup, decision support, and database error recovery.Creation of Snapshot Mirrors
Caution
To avoid data inconsistencies, do not use the same snapshot with different point-in-time copy applications. If you require snapshot mirrors for more than one application, configure at least one snapshot mirror that is dedicated to each application.
If the existing volume was created before release 4.0 of VxVM, and it has any attached snapshot plexes, is associated with any snapshot volumes, or has any dedicated DRL logs, follow the procedure given in the section "Upgrading Existing Volumes to Use Version 20 DCOs" in the "Administering Volumes" chapter of the VERITAS Volume Manager Administrator's Guide. The procedure given in this section assumes that no snapshot plexes, snapshot volumes, or DRL logs are associated with the volumes.
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