Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

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.
However, if the primary host is not also the master node, most Volume Manager
operations on shared disk groups are best 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 To make an off-host backup of an online
database and 10 through 13 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:
■ DB2 provides the write suspend command to temporarily suspend I/O
activity for a database. As the DB2 database administrator, use a script
such as that shown in the example.
See “Script to suspend I/O for a DB2 database” on page 516.
Note that to allow recovery from any backups taken from snapshots, the
database must be in LOGRETAIN RECOVERY mode.
■ 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 the example.
See “Script to put an Oracle database into hot backup mode” on page 515.
■ Sybase ASE from version 12.0 onward provides the Quiesce feature to
allow temporary suspension of writes to a database. As the Sybase database
administrator, put the database in quiesce mode by using a script such as
that shown in the example.
See “Script to quiesce a Sybase ASE database” on page 516.
Online database backup
Making an off-host backup of an online database
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