VERITAS Volume Manager 4.1 Migration Guide

Converting LVM to VxVM

Converting LVM Volume Groups to VxVM Disk Groups

Chapter 28

After analysis you know which volume group or groups you want to convert to VxVM disk

groups. Up to this point, you have not altered your LVM conﬁguration.

By taking the next step (completing the conversion to VxVM), you are signiﬁcantly changing

access to your storage.

Although the conversion process does not move, or in any other way affect user data, you are

strongly encouraged to back up all data on the affected disks. Similarly, you should back up

the LVM conﬁguration itself.

During a conversion, any spurious reboots, power outages, hardware errors or operating

system bugs can have unpredictable and undesirable consequences. You are advised to be on

guard against disaster with a set of veriﬁed backups.

Backing up an LVM conﬁguration Use the vgcfgbackup (1M) utility before running

vxvmconvert to save a copy of the LVM conﬁguration.

You can back up the LVM volumes using the following command:

# vgcfgbackup -f pathname/filename vol_grp_name

Be sure to use the -f option to save the data into a ﬁle other than the default. vxvmconvert

uses LVM utilities which themselves save the conﬁguration using vgcfgbackup. If you do not

use the -f option when you attempt to backup the conﬁguration, the conversion process will

overwrite your attempted backup.

A copy of this LVM conﬁguration should be kept off-line on tape or some other medium for use

in the event of a disaster during conversion.

For example, to put a copy on tape, use the following command:

# tar cvf /dev/rmt/c3t0d0BEST /vgbackups/vg08

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. (See section “Example: displaying the

vxvmconvert menu” on page 20) 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.