VERITAS Volume Manager 3.5 Migration Guide (August 2002)

Converting LVM Volume Groups to VxVM Disk Groups Final 24 July 2002
12 VERITAS Volume Manager Migration Guide
Note You can use the vxcp_lvmroot(1M) command to create a VxVM root disk on a
spare physical disk from the contents of the existing LVM root disk. Similarly, you
can use the vxres_lvmroot(1M) command to recreate an LVM root disk on a
spare disk from the contents of the VxVM root disk. For more information, see the
section “Rootability” in the “Administering Disks” chapter of the VERITAS Volume
Manager Administrator’s Guide.
◆ A volume group containing mirrors using the Mirror Write Cache feature for volume
consistency recovery.
Users should be aware that when converting mirrored LVM volumes to VxVM, some
ofthese volumeswill likelyhave theMirrorWrite Cache consistencyrecoverymethod
in force on the volume. The vxvmconvert utility can convert these volumes, but
must use the Dirty Region Logging (DRL) feature to obtain the same level of
functionality. However, since Dirty Region Logging requires some user space to be
available for the log, a conversion could fail due to an MWC volume being full,
leaving no space for the DRL log. However it is very unlikely that this situation
would occur. Note that the MWC and DRL are used only when the system crashes or
is improperly shut down, to quickly bring all mirrors in the volume back into a
consistent state.
◆ A volume group containing the /usr file system.
For this release, a volume group containing the /usr file system cannot be converted
because vxvmconvert needs access to files in /usr.
◆ Volume groups with any dump or primary swap volumes.
vxvmconvert will not convert any volume group with dump or primary swap
volumes. These are volumes known to the boot process. However, swap volumes on
volumes other than the root volume can be converted (as long as this volume is not in
the same volume group as the root volume).
◆ Volume group disks used in MC/ServiceGuard clusters.
The conversion process does not support conversion of any volume group that is
marked as a member of a MC/ServiceGuard or OPS Edition high availability cluster.
The volume group must be deactivated and removed from membership in the high
availability cluster before it can be converted.
◆ Volume groups used for cluster lock disks.
The conversion process does not support conversion of a volume group that contains
a disk that is being used for a cluster lock disk for an MC/ServiceGuard cluster.
◆ Volume groups with any disks that have bad blocks in the bad block directory.