Veritas Volume Manager 5.0 Migration Guide, HP-UX 11i v3, First Edition, May 2008

30 Converting LVM to VxVM
Restoring the LVM volume group configuration
Rollback to LVM using vxvmconvert
Rollback replaces the VxVM disk groups with the original LVM volume groups.
During conversion, vxvmconvert saves a “snapshot” of the original LVM
metadata and associated configuration files, such as /etc/fstab and LVM device
files. It restores only the LVM metadata and configuration files from this
snapshot; user data is not changed. This method can only be used if no changes
have been made to the configuration since the conversion.
For example, if a disk has been added to the disk group or if the names of any
logical volumes have changed, you cannot use the rollback method.
Note: In many cases, if you choose the rollback method and the configuration
has changed, you receive an error and must use the full restore method.
If you used the workaround of creating symbolic links from the old LVM names
to the new VxVM names described in “step 5. Planning for new VxVM logical
volume names,” you must remove the symbolic links you created before
beginning the rollback.
This “snapshot” is kept on the root file system. The presence of this snapshot
should not be taken as assurance that full off-line backups will not be needed.
See “4. Backing up your LVM configuration and user data” for specific
information on backups.
To rollback to LVM from the VxVM conversion, run
vxvmconvert and choose
option 3. See “Example: VxVM to LVM rollback” on page 43 for illustration.
Caution: Do not use this option unless you are certain that you want to restore
LVM volume groups. Once this is run, the VxVM disks that were created as a
result of the original conversion from LVM to VxVM no longer exists. This
option is not a full complement to
vxvmconvert. It simply writes the saved LVM
metadata back on top of the disks. Those data can only be considered valid for
the period of time when the logical volumes are off-line. If the VxVM
configuration has been brought online, the metadata in the rollback snapshot
should be considered obsolete. See “Full LVM restoration” on page 31 for
specific information.