Veritas Storage Foundation™ 5.0.1 for Oracle RAC Installation, Configuration, and Administrator's Guide Extracts for the HP Serviceguard Storage Management Suite on HP-UX 11i v3

storage is the only aspect of using Database FlashSnap that requires the system administrator’s
participation.
To use Database FlashSnap, a database administrator must first define their snapshot requirements.
For example, they need to determine whether off-host processing is required and, if it is, which
host should be used for it. In addition, it is also important to consider how much database
downtime can be tolerated. Database snapshot requirements are defined in a file called a snapplan.
The snapplan specifies snapshot options that will be used when creating a snapshot image (such
as whether the snapshot mode will be online, offline, or instant). After creating the snapplan,
the database administrator must validate it to ensure that it is correct. During validation the
snapplan is copied to the repository before using it to create a snapshot. Depending on the
validation results, the database administrator may need to modify the snapplan or the system
administrator may need to adjust the storage configuration.
After storage is configured as specified in the snapplan and the snapplan has been validated,
the database administrator can create snapshots of the database and create database clones based
on the snapshots on either the same host or a secondary one.
A database clone can be used on a secondary host for off-host processing, including
decision-support analysis and reporting, application development and testing, database backup,
and logical error recovery. After a user has finished using the clone on a secondary host, the
database administrator can shut down the clone and move the snapshot database back to the
primary host. Regardless of whether a snapshot is used on the primary or secondary host, it can
be resynchronized with the primary database using Database FlashSnap. Database FlashSnap
utilizes Veritas Volume Manager FastResync to quickly resynchronize the changed section
between the primary and snapshot.
Database FlashSnap can also be used to recover the primary copy of the database if it becomes
corrupted by overwriting it with the snapshot. You can recover the primary database with a
snapshot using the reverse resynchronization functionality of Database FlashSnap.
Using Database FlashSnap Commands
The Database FlashSnap feature consists of three commands:
• dbed_vmchecksnap(used on the primary host)
Creates and validates the snapshot plan used to create a snapshot image of an Oracle database.
You can also use dbed_vmchecksnap to copy, list, or remove a snapplan or make sure the
storage is configured properly for the task. dbed_vmchecksnap is also used on the secondary
host to list the snapplan.
• dbed_vmsnap (used on the primary host)
Creates a snapshot image of an Oracle database by splitting the mirror volumes used by the
database. You can also use dbed_vmsnap to resynchronize snapshot volumes with their
original volumes. The command also allows you to resynchronize the original volumes from
the data in the snapshot volumes, which is useful if the original volumes become corrupted.
Resynchronizing the original volumes from the snapshot volumes is known as reverse
resynchronization.
NOTE: Snapplan creation and validation is only supported on CVM master node.
• dbed_vmclonedb (used on the primary or secondary host)
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.
About Veritas Database FlashSnap 51