VERITAS Volume Manager 3.1 Migration Guide

Converting LVM to VxVM
Converting LVM Volume Groups to VxVM Disk Groups
Chapter 2 31
3. Taking actions to make conversion possible if analysis fails
Analysis may fail for any of the reasons listed in the section “Volume
Group Conversion Limitations””.
Messages from vxvmconvert will explain the type of failure and any
actions that can be taken before retrying the analysis. Refer to Appendix
A, Conversion Error Messages, for complete details of specific error
messages and actions.
4. Backing up your LVM configuration and user data
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