Veritas Volume Manager 5.0.1 Migration Guide, HP-UX 11i v3, First Edition, November 2009

Planning for new VxVM logical volume names
When you change from LVM volumes to VxVM volumes, the device names by
which your system accesses data are changed. LVM creates device nodes for its
logical volumes in /dev under directories named for the volume group. VxVM
creates its device nodes in /dev/vx/dsk and /dev/vx/rdsk. When conversion is
complete, the old LVM device nodes are gone from the system, and the system
will access data on the device nodes in /dev/vx.
This change in names can present problems. Any application that refers to specific
device node names will be at risk when these names change. Similarly, any files
that record specific device node names for use by applications can be problematic.
The most obvious area where this problem arises is in /etc/fstab. To handle this
problem, vxvmconvert will rewrite the fstab with the new VxVM names when
conversion is done so that fsck, mount, and related utilities will behave as they
did before the conversion.
There are potentially many other applications, though, that may be put at risk by
the name changes in conversion. vxvmconvert cannot help with these. The system
administrator must examine the mechanisms used in each of the following areas
to see if they reference LVM device names:
■ Databases run on raw logical devices may record the name of that device node.
■ Backup systems may do device level backups based on device node names
recorded in private files. Also labeling of the backups may record device names.
■ Scripts run by cron(1M).
■ Other administrative scripts.
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.
29Converting LVM to VxVM
Converting LVM volume groups to VxVM disk groups