VERITAS Volume Manager 3.5 Migration Guide (August 2002)

Chapter 2, Converting LVM to VxVM
Final 24 July 2002 Restoring the LVM Volume Group Configuration
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This “snapshot” iskept on therootfile system. Thepresenceof 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 36 for illustration.
Caution Do not use this option unless you are certain that you want to restore LVM
volume groups.Once thisisrun, the VxVMdisks that werecreatedas a result of
the original conversionfrom LVM to VxVMno longerexists. This optionis nota
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 23 for specific
information.
Full LVM Restoration
If you need to restore the original LVM configuration, but changes have been made to the
VxVM configuration, you cannot use the rollback option of vxvmconvert. In this case,
you must restore the user data in addition to restoring the old LVM metadata and
associated configuration files. You may need to use this method if the disks in use by the
LVM/VxVM volumes were corrupted during or after conversion.
Note The snapshot of LVM internal data is kept on the root filesystem.
To use this method, you must have backed up data located on all the volume groups’
logical volumes before conversion to VxVM.
Restoration of LVM volume groups is a two-step process consisting of a restoration of
LVM internal data (metadata and configuration files), and restoration of user or
application data.
The process is limited to restoring the state of the logical volumes as they existed prior to
conversion to VxVM disks. If the data has changed on the volumes during the time they
were VxVM volumes, those changes are lost once you restore the LVM configuration and
saved user data.
To do a full restoration of the original LVM configuration, do the following:
1. Use vgrestore to restore LVM internal data.
# vgrestore vol_grp_name