VERITAS Storage Foundation 4.1 Oracle Administrator's Guide

Chapter 10, Using Database FlashSnap for Backup and Off-Host Processing
Prerelease 8 September 2005, 8:55am How VERITAS Database FlashSnap Works
201
Mounts and starts a clone database using snapshot volumes. It can also shut down a clone
database and deport its volumes, as well as restart a clone database that has been shut down.
The snapshot image can be brought up on the same host running the primary database or on a
secondary host.
All of these commands can be executed by the Oracle database administrator and do not require
superuser (root) privileges.
Note Database FlashSnap operations can be executed from either the command line or the GUI.
Database FlashSnap Options
Database FlashSnap offers three options for creating database snapshots. The option you choose is
specified in the snapplan.
◆ online
With this option, the tablespaces are put into online backup mode before the snapshot is
created. This type of snapshot is also a valid database backup. Select this option if you are
performing a point-in-time recovery from logical errors.
◆ instant
With this option, the database can be up and running, and the tablespaces do not need to be put
into online backup mode before the snapshot is created. However, all the file systems used by
the database (including those containing the online redo logs and control files) are temporarily
frozen and the cache is flushed before the snapshot is created. By freezing the file systems, the
snapshot will be a consistent point-in-time image of the database from which a database clone
can be created.
An instant snapshot can be used to guard against data corruption or for off-host
decision-support queries. However, it is not a valid database backup and cannot be used to
perform a point-in-time recovery or off-host backup since tablespaces are not put into online
backup mode before the snapshot is created. The instant option is much faster than the online
option.
◆ offline
The offline option can be used to clone or back up a database. With this option, the
database must be shut down when the snapshot is created. and online redo logs are required.
This type of snapshot is a valid database backup.
Note In this release of VERITAS Storage Foundation for Oracle, Database FlashSnap supports
third mirror break-off snapshots only. Third mirror break-off snapshots are fully
synchronized, full-sized snapshots. See the VERITAS Volume Manager Administrator’s
Guide for more information.