VERITAS Volume Manager 4.1 Migration Guide

Converting LVM to VxVM
Converting LVM Volume Groups to VxVM Disk Groups
Chapter 210
• Scripts run by cron (1M).
• Other administrative scripts.
A Workaround vxvmconvert records a mapping between the names of the LVM device nodes
and VxVM device nodes. This data can be used to create symbolic links from the old LVM
volume to the new VxVM device names. The mapping is recorded in the file:
/etc/vx/reconfig.d/vgrecords/vol_grp_name/vol_grp_name.trans
This file provides information on how to proceed further to link the old LVM volume names to
the new VxVM device names.
CAUTION This method of resolving the naming problem has risks. The symbolic links can
become stale. For example, if a database refers to /dev/vx/rdsk/vol1 through
a symbolic link /dev/vg00/rvol1 ("the old LVM name)", and if the underlying
VxVM volume configuration is changed in any way, the database could refer to
a missing or different volume.
NOTE You may want to use this symbolic link approach to ease the transition to
VxVM. You can set up the symbolic links after the successful conversion to
VxVM. Then, you can do the investigation on a case by case basis for each
volume. Once you are satisfied that there are no problems introduced by the
name change, the symbolic link to that volume can be removed. You must be
careful to maintain a static VxVM volume configuration during this transition
period.
Over time, the ultimate goal should be that the underlying VxVM naming is used by all
applications, and that there are no indirect references to those volumes.
6. Stopping application access to volumes in the volume group to be converted
No applications can be active on the LVM volume group undergoing conversion. Before
attempting to convert any volume group, you must ensure that applications using that group
are down. This involves stopping databases, unmounting file systems, etc.
NOTE If you are converting a volume with swap space on it, the conversion requires a
reboot. The swap space cannot be taken out of control of the operating system
with a shutdown to single user mode.