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 Summary of Database Snapshot Steps
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Summary of Database Snapshot Steps
You can use Database FlashSnap commands to create a snapshot of your entire database on the
same host or on a different one. Three types of snapshots can be created: online, offline, or
instant.
If the SNAPSHOT_MODE specified in the snapplan is set to online, dbed_vmsnap first puts the
tablespaces to be snapshot into backup mode. After the snapshot is created, the tablespaces are
taken out of backup mode, the log files are switched to ensure that the extra redo logs are archived,
and a snapshot of the archive logs is created.
If the SNAPSHOT_MODE is set to offline, the database must be shut down before the snapshot
is created. Online redo logs and control files are required and will be used to ensure a full database
recovery.
If the SNAPSHOT_MODE is set to instant, tablespaces are not put into and out of backup mode.
Online redo logs and control files are required and will be used to ensure a full database recovery.
Both online and offline snapshots provide a valid backup copy of the database. You can use the
snapshot as a source for backing up the database or creating a clone database for decision-support
purposes. Instant snapshots do not represent a valid backup copy for point-in-time recovery.
The sections that follow explain how to create snapshots of all volumes on a database using the
snapplan. Optionally, you can use the VxVM command (vxsnap) to create volume snapshots.
However, unlike the Database FlashSnap commands, the vxsnap command does not automate
disk group content reorganization functions. For more information about the vxsnap command,
see VERITAS Volume Manager Administrator’s Guide.
Note Make sure the volumes used by the database are configured properly before attempting to
take a snapshot. This requires superuser (root) privileges.
Note Anytime you change the structure of the database (for example, by adding or deleting
datafiles, converting PFILE to SPFILE, or converting SPFILE to PFILE), you must run
dbed_update.
Note Database FlashSnap commands must be run by the Oracle database administrator.
▼ To create a snapshot image of a database
1. Perform the steps in “Creating a Snapshot Mirror of a Volume or Volume Set Used by the
Database” on page 206.
2. Use the dbed_vmchecksnap command to create a snapplan template and check the volume
configuration to ensure that it is valid for creating volume snapshots of the database.