VERITAS Volume Manager 5.0 Migration Guide (September 2006)

23Converting LVM to VxVM
Converting LVM volume groups to VxVM disk groups
Note: The vxvmconvert utility itself also saves a snapshot of the LVM metadata in the
process of conversion for each disk. This data is saved in a different format from that of
vgcfgbackup. It can only be used via the vxvmconvert program. With certain
limitations, you can reinstate the LVM volumes after they have been converted to VxVM
using this data (seeExample: displaying the vxvmconvert menu” on page 31). Even
though
vxvmconvert provides this level of backup of the LVM configuration, you are
advised to use vgcfgbackup before running vxvmconvert.
Backing up user data
To back up user data, use your regular backup processes.
Caution: Before you do the backup, you should carefully review “step 9. Implementing
changes for new VxVM logical volume names.” Backup processes and systems
themselves may have dependencies on the volume names currently in use on your system.
The conversion to VxVM changes those names. You are advised to understand the
implications name changes have for restoring from the backups you are about to make.
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 backup 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.
5. 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
.