LVM Volume Group Dynamic LUN Expansion (DLE) and Contraction (DLC) (September 2009)
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vgmodify –B n –n –t vgname <PV to convert> (with–n).
vgmodify –B n –t vgname <PV to convert> (without –n).
vgmodify –B n –o –r vgname <PV to convert>.
2. Select the entry from the output of the three commands that meets the requirements. If using a
setting from the –tn table and this requires physical extent renumbering lower, run
vgmodify –B n –tnv vgname <PV to convert> and check that no disks need the
first physical extent to be made free. If they do, free-up this extent on each disk using
pvmove, lvreduce, or lvremove.
3. Run vgmodify –B n –r –e max_pe –p max_pv vgname <PV to convert>, where
max_pe and max_pv are the chosen values, to test the change.
4. When a maintenance window is available, deactivate the volume group and run vgmodify
with the same options as before, but without –r or, if using the –o settings, -B n –o vg
name <PV to convert>.
Example
1. Run vgmodify in table mode and note any bootable disks reported.
# vgmodify -tv vg02
Volume Group configuration for /dev/vg02 has been saved in
/etc/lvmconf/vg02.conf
Current Volume Group settings:
Max LV 255
Max PV 16
Max PE per PV 5119
PE Size (Mbytes) 4
VGRA Size (Kbytes) 736
VGRA space (Kbytes) on Physical Volumes with extents in use:
PV current -n
/dev/rdsk/c0t0d0 768 768
/dev/rdsk/c0t1d0 896 4096
/dev/rdsk/c0t3d0 896 4096
Summary 768 768
The space available for the configuration data will be limited by
having bootable disks. If this is not a boot VG then consider
changing the type, using -B n, of the following bootable disks:
/dev/rdsk/c1t0d0
Volume Group optimized settings (no PEs renumbered):
max_pv(-p) max_pe(-e) Disk size (Mb)
3 30460 121840
4 22780 91120
5 18172 72688
* Entries deleted for brevity
39 2300 9200
44 2044 8176
45 1808 7232
* Entries deleted for brevity
255 252 1008
The space for the VGRA on c0t0d0 is 768 KB regardless of whether –n is used or not. This is
expected for a bootable disk. Note how this affects the summary and is limiting both –n and
non –n sizes.