Veritas FlashSnap Point-In-Time Copy Solutions 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

49Decision support
Creating a replica database on the same host
To set up a replica database to be used for decision support on the primary
host
1 If you have not already done so, prepare the host to use the snapshot volume
that contains the copy of the database tables. Set up any new database logs
and configuration files that are required to initialize the database.
2 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 27 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/snapvol=svol1/nmirror=2 \
source=vol2/snapvol=svol2/nmirror=2 \
source=vol3/snapvol=svol3/nmirror=2
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 28 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
See the section “Creating a Share Cache Object” in the “Administering
Volume Snapshots” chapter of the Veritas Volume Manager Administrator’s
Guide for more information.
Note: This step sets up the snapshot volumes, and starts tracking changes
to the original volumes. When you are ready to create the replica database,
proceed to step 3.