Dynamic LUN expansion using vgmodify

[IT_2007]

vgmodify works pretty well if you want to add more disks to the existing volume group. But it really doesn't support if SAN team increases size of DISK on existing volume group. Any body knows why OS can't see change in the total size of disk when SAN team increases DISK instead of adding new disks. Is it supported on new HP-UX release?

Thanks.

[Torsten. · Accepted solution]

see http://docs.hp.com/en/B2355-60130/vgmodify.1M.html

"Detect and handle physical volume size changes.

To take advantage of a physical volume size increase, it may be necessary to run vgmodify to increase the maximum number of physical extents for the volume group.

The detection of physical volume size changes (LUN size expansion or contraction) is automatic, with the handling taking place unless the -r or -t options have been used."

Can you provide more details (commands run etc...)?

[Patrick Wallek]

Yes, this is supported on HP-UX 11iv3 (11.31) and I believe this functionality has been ported back to HP-UX 11iv2 (11.23).

[melvyn burnard]

Take a look at:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1139008

[IT_2007]

attached 64GB SAN disk and created vgtest and logical volume of 64GB. Ran vgmodify with -n option like this:

vgmodify -n -e 33532 -p 15 -v vgtest

SAN team increased c2t0d2 disk size from 64GB to 128GB but my OS still sees 64GB.

=> pvdisplay /dev/dsk/c2t0d2

--- Physical volumes ---
PV Name /dev/dsk/c2t0d2
VG Name /dev/vgtest
PV Status available
Allocatable yes
VGDA 2
Cur LV 1
PE Size (Mbytes) 4
Total PE 16382
Free PE 2
Allocated PE 16380
Stale PE 0
IO Timeout (Seconds) default
Autoswitch On
Proactive Polling On

[IT_2007]

I got it. Missed the following command to run.

vgmodify -v -o vgtest which does final optimization.

[IT_2007]

need to run vgmodify -v -o command.