VERITAS FlashSnap Point-In-Time-Copy Solutions Administrator's Guide

Chapter 3, Online Database Backup
Making a Backup of an Online Database on the Same Host
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To make a backup of an online database on the same host:
1. Use the following command to make a full-sized snapshot, snapvol, of the tablespace volume
by breaking off plexes from the original volume:
# vxsnap -g volumedg make source=volume/newvol=snapvol/nmirror=N
The nmirror attribute specifies the number of mirrors, N, in the snapshot volume.
If the volume does not have any available plexes, or its layout does not support plex break-off,
use the procedure described in “Creating a Volume for Use as a Full-Sized Instant Snapshot”
on page 23 to prepare an empty volume for the snapshot, and then use the following command
to create the snapshot:
# vxsnap -g volumedg make source=volume/snapvol=snapvol
If a database spans more than one volume, specify all the volumes and their snapshot volumes
as separate tuples on the same line, for example:
# vxsnap -g dbasedg make source=vol1/newvol=svol1 \
source=vol2/newvol=svol2 source=vol3/newvol=svol3
If you want to save disk space, you can use the following command to create a
space-optimized snapshot instead:
# vxsnap -g volumedg make \
source=volume/newvol=snapvol/cache=cacheobject
The argument cacheobject is the name of a pre-existing cache that you have created in the disk
group for use with space-optimized snapshots. See “Creating a Shared Cache Object” on
page 24 for more information.
If several space-optimized snapshots are to be created at the same time, these can all specify
the same cache object as shown in this example:
# vxsnap -g dbasedg make source=vol1/newvol=svol1/cache=dbaseco \
source=vol2/newvol=svol2/cache=dbaseco \
source=vol3/newvol=svol3/cache=dbaseco
Note This step sets up the snapshot volumes ready for the backup cycle, and starts tracking
changes to the original volumes. When you are ready to make a backup, proceed to
step 2.