topic Re: Added a new LUN but unable to lvextend LV in Operating System - HP-UX

Added a new LUN but unable to lvextend LV

Mr. John Kerr — Fri, 10 Nov 2006 05:51:33 GMT

Hi, i added a new LUN of 25GB to our va7410
and carried out the following commands.
insf -e
pvcreate /dev/dsk/c14t0d7
vgextend /dev/vg02 /dev/dsk/c14t0d7 and alt links.
umount /dev/vg02/lvoraerp
lvextend -L 127920 /dev/vg02/lvoraerp
got the error: Not enough free physical extents.

vgdisplay -v vg02 - looks like this
--- Volume groups ---
VG Name /dev/vg02
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 16
Cur PV 5
Act PV 5
Max PE per PV 1599
VGDA 10
PE Size (Mbytes) 16
Total PE 7995
Alloc PE 6396
Free PE 1599
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

Any ideas.

Re: Added a new LUN but unable to lvextend LV

Peter Godron — Fri, 10 Nov 2006 06:03:39 GMT

John,
you only have 1599*16Mb =25584 Mb available.
You are trying to increase lvoraerp to 127920 Mb. How big is lvoraerp it at the moment? Also review your max PE per PV and Total PVs.

Re: Added a new LUN but unable to lvextend LV

Yang Qin_1 — Fri, 10 Nov 2006 06:04:37 GMT

Hi, can you post the first pages from "lvdisplay -v /dev/vg02/lvoraerp|more"? Is the lvol is mirrored with "Allocation strict"?

Yang

Re: Added a new LUN but unable to lvextend LV

Steven E. Protter — Fri, 10 Nov 2006 06:11:48 GMT

Shalom,

Normally to recognize disk space a reboot and/or insf -C disk is required.

SEP

Re: Added a new LUN but unable to lvextend LV

Mr. John Kerr — Fri, 10 Nov 2006 06:25:08 GMT

Hi,
The Logical Volume:lvoraerp is currently
Space Available in Volume Group (Mbytes): 25584
Current Logical Volume Size (Mbytes): 102336

--- Logical volumes ---
LV Name /dev/vg02/lvoraerp
VG Name /dev/vg02
LV Permission read/write
LV Status available/syncd
Mirror copies 0
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 102336
Current LE 6396
Allocated PE 6396
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation PVG-strict/distributed
IO Timeout (Seconds) default

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c14t0d0 1599 1599

Re: Added a new LUN but unable to lvextend LV

Yang Qin_1 — Fri, 10 Nov 2006 06:32:07 GMT

Please check /etc/lvmpvg file. You may need to update that file after you extend the vg with a new disk.

Yang

Re: Added a new LUN but unable to lvextend LV

Sandman! — Sat, 11 Nov 2006 23:13:08 GMT

Hi John,

Try lvextend'ing lvoraerp onto the newly added LUN i.e.

# lvextend -L 127920 /dev/vg02/lvoraerp /dev/dsk/c14t0d7

~cheers

Re: Added a new LUN but unable to lvextend LV

Mark Nieuwboer — Sun, 12 Nov 2006 08:32:23 GMT

Hi John,

I have a question, is the new disk bigger dan the disk already in the volume group.
If thats the case you have to export and import the volume group to make the volumegroup aware of the bigger disk.
For now is the limmet the disk size of the biggest disk when you created the volume group.
You have to make the volumegroup aware of a disk that is 25 Gig big.

grtz. Mark

Re: Added a new LUN but unable to lvextend LV

Hein van den Heuvel — Sun, 12 Nov 2006 16:29:05 GMT

Mark, Nice thought on the max size, but the numbers appear to work, and are relatively simple:

Old: 4 * 1599 * 16 = 102336
Add: 1 * 1599 * 16 = 25584
New: 5 * 1599 * 16 = 127920

John, I think the system refuses the request due to the "Allocation PVG-strict/distributed" setting.
You could try lvchange to change that.

However... in the current setup all allocation, and with the hopefully the IO, is supposed to be spread evenly over the existing 4 PV's.

Adding the 5'th in non-strict mode will cause all future allocation do come from that 1 specific lun. If, at the VA7410 end of it, that lun is created on a limited number of drive, then those may become 'too hot'. It is not uncommon to have recenetly allocated data be the most active part of a DB. Of course if the 5th lun is just an other slice of a bulk disk group then it matters little.

See also:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=841424

hth,
Hein.

Re: Added a new LUN but unable to lvextend LV

Mr. John Kerr — Tue, 14 Nov 2006 06:09:54 GMT

Hi,

I think the strict allocation policy may be the answer, i will be arranging some downtime with the users so that i can try out the lvchange.