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

See “Implementing changes for new VxVM logical volume names” on page 413.
File system back up of user data
You can use the backup utility that you normally use to back up data on your
logical volumes. For example, to back up logical volumes that contain file systems,
the fbackup(1M) command can be used to back up the data to tape.
For example, to back up the data on /dev/vg01/lvol3 mounted on /foodir, use
the following command:
# fbackup -0i /foodir -f /dev/rmt/c0t0d0BEST
Non-file system back up
If a logical volume you are converting does not contain a file system, and is being
used directly by an application (such as a database application), use the backup
facilities provided by the application. If no such facility exists, consider using the
dd command.
Planning for new VxVM logical volume names
When you change from LVM volumes to VxVM volumes, the device names by
which your system accesses data are changed. LVM creates device nodes for its
logical volumes in /dev under directories named for the volume group. VxVM
creates its device nodes in /dev/vx/dsk and /dev/vx/rdsk. When conversion is
complete, the old LVM device nodes are gone from the system, and the system
will access data on the device nodes in /dev/vx.
This change in names can present problems. Any application that refers to specific
device node names will be at risk when these names change. Similarly, any files
that record specific device node names for use by applications can be problematic.
The most obvious area where this problem arises is in /etc/fstab. To handle this
problem, vxvmconvert will rewrite the fstab with the new VxVM names when
conversion is done so that fsck, mount, and related utilities will behave as they
did before the conversion.
There are potentially many other applications, though, that may be put at risk by
the name changes in conversion. vxvmconvert cannot help with these. The system
administrator must examine the mechanisms used in each of the following areas
to see if they reference LVM device names:
■ Databases run on raw logical devices may record the name of that device node.
■ Backup systems may do device level backups based on device node names
recorded in private files. Also labeling of the backups may record device names.
409Offline data migration
Converting LVM to VxVM