Veritas Storage Foundation 5.0 for Oracle RAC Configuration Guide Extracts for HP Serviceguard Storage Management Suite, Second Edition, May 2008

Using FlashSnap for Backup and Recovery

Summary of Database Snapshot Steps

Chapter 5

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. Create a snapshot mirror of a volume or volume set.

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.

The snapplan contains detailed database and volume configuration information that

is needed for snapshot creation and resynchronization. You can modify the snapplan

template with a text editor.