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

37Online database backup
Making an off-host backup of an online database
Note: It is assumed that you have already prepared the volumes containing the
file systems for the datafiles to be backed up as described in “Setting up volumes
for instant snapshots” on page 21. For an Oracle database, it is not necessary to
create snapshots of the volumes containing the file systems for the redo log
volumes or archived logs.
If the database is configured on volumes in a cluster-shareable disk group, it is
assumed that the primary host for the database is the master node for the
cluster. If the primary host is not also the master node, all VxVM operations on
shared disk groups must be performed on the master node.
The procedure in this section is designed to minimize copy-on-write operations
that can impact system performance. You can also implement this procedure on
a single host by omitting steps 5 through 8 and 10 through13 that split, deport,
reimport and rejoin the snapshot disk group.
To make an off-host backup of an online database
1 On the primary host, add one or more snapshot plexes to the volume using
this command:
# vxsnap -g volumedg addmir volume [nmirror= N ] \
[alloc=
storage_attributes ]
By default, one snapshot plex is added unless you specify a number using
the
nmirror attribute. For a backup, you should usually only require one
plex. You can specify storage attributes (such as a list of disks) to determine
where the plexes are created.
2 Suspend updates to the volumes. Oracle supports online backup by
temporarily suspending updates to the datafiles of the tablespaces, provided
that the database is running in archive mode and the tablespaces are online.
As the Oracle database administrator, put each tablespace into hot backup
mode using a script such as that shown in “Script to put an Oracle database
into hot backup mode” on page 65.
3 Use the following command to make a full-sized breakoff snapshot, snapvol,
of the tablespace volume by breaking off the plexes that you added in step 1
on page 37 from the original volume:
# vxsnap -g volumedg make \
source=
volume /newvol= snapvol /nmirror=N \
[alloc=
storage_attributes ]
The nmirror attribute specifies the number of mirrors, N, in the snapshot
volume.
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: