VERITAS Volume Manager 3.5 Migration Guide (September 2004)
Chapter 3
Command Differences
Comparison of LVM and VxVM Tasks
48
VxVM The Multipathing disk devices in the
Volume Manager represent virtual devices
with one or more physical access paths to
a particular physical disk. Dynamic
Multipathing provides reliability of disk
access by dynamically switching to
another physical path in the event of
failure of a path.
The DMP feature in VxVM sets up links
automatically. It is not required to set up links
separately.
Refer to the manual page vxdmp (7) and the
VERITAS Volume Manager Administrator’s Guide
for more information on DMP.
LVM Create a mirrored logical volume. lvcreate -l
num_log_extents
-m 1 -n
mirr_lv
/dev/
vol_grp
VxVM Create a mirrored volume/plex
or add a mirror to an existing volume.
vxassist make
vol_name length
layout=mirror
LVM Reduce a single/double mirrored logical
volume to an unmirrored logical volume.
Remove a mirrored logical volume.
lvreduce -m 0 /dev/
vol_grp
/
mirr_lv
lvremove /dev/
vol_grp
/
mirr_lv
VxVM Remove mirrors or reduce the number of
plexes/mirrors.
Remove a volume with the plexes
associated with it.
vxplex -o rm dis
plex_name
vxedit -rf rm
vol_name
LVM Increase the number of mirror copies. lvextend -m 2 /dev/
vol_grp
/
lvol_name
VxVM Add mirrors to a volume or increase the
number of plexes.
vxassist mirror
vol_name
LVM Convert a mirrored logical volume into
two logical volumes.
Split a logical volume.
lvsplit -s backup /dev/
vol_grp
/
lvol_name
VxVM Snapshot a volume and create a new
volume.
vxassist snapshot
vol_name new_vol_name
LVM Combine two logical volumes back into a
mirrored logical volume
lvmerge /dev/
vol_grp
/
split_vol_name
\
/dev/
vol_grp
/
lvol_name
split_vol_name
= active logical volume
VxVM Returns the snapshot plex to the original
volume from which it was snapped.
vxassist snapback
new_vol_name
LVM Move a mirrored logical volume from one
disk to another.
pvmove -n /dev/
vol_grp
/
lvol_name
\
/dev/dsk/
disk_name
/dev/dsk/
disk_name2
VxVM Move a plex. vxplex mv
orig_plex new_plex
Table 3-2 LVM and VxVM Task Comparison (Continued)
Task
Type
Description Example