Software Suite for Oracle Instruction Manual

2.15
Virtual Copy Policy
Recovery Manager for Oracle User’s Guide
2.8 Virtual Copy Policy
3PAR Recovery Manager provides the capability to limit the maximum number of virtual copies
allowed per database instance at any time.
For example, a policy can be set to only allow twelve virtual copies at any time for a database.
Recovery Manager always maintains the twelve latest virtual copies by removing the oldest
virtual copy before creating a new copy. The default, and maximum allowed, number is 500,
meaning that up to 500 read-only virtual copies can be created if you have sufficient snapshot
space.
2.9 Database Rollback from a Virtual Copy
When a database is corrupted, you can restore the database to the most recent database
images from the most recently created virtual copy by using the rollback utility.
2.9.1 The Database Rollback Utility
3PAR Recovery Manager’s database rollback utility (vcdba_rollback) promotes a virtual
copy's volumes back to its base virtual volumes. In other words, the base virtual volumes used
by the database are rolled back to the virtual copy volumes. Once the rollback process
completes successfully, the base virtual volumes are exactly the same as the virtual copy
volumes. If the base volume size has been changed since the virtual copy was taken, the
rollback process will not affect the new size.
■ When rolling back from an online virtual copy, both datafile and archive log virtual
volumes are rolled back by default. Use the
-o option to rollback only datafile virtual
volumes or only archive log virtual volumes.
■ When rolling back from an offline virtual copy, only datafile virtual volumes are rolled
back.
■ When rolling back from an archive log virtual copy, only archive log virtual volumes are
rolled back.
The following restrictions apply when rolling back a virtual copy:
■ The online redo logs and control file should not reside on the same virtual volumes used by
the datafiles and archive logs. Otherwise, they will be rolled back along with the datafile
and archive log virtual volumes.