lvextend fails..not enough physical extents available

[Dave Chamberlin]

Greetings, I have a va7410 connected to my rp8400 (running hpux 11.23). I added 30G to vg01 and want to extend u01 in that vg by 8G. I am getting:lvextend: Not enough free physical extents available.
Logical volume "/dev/vg01/u01" could not be extended.
lvextend: Couldn't retrieve the list of the physical volumes belonging to volume group "/dev/vg01".
Failure possibly caused by strict allocation policy

Since this is a virtual disk, why am I getting this error? I am attaching vgdisplay for the vg.

[Patrick Wallek]

Pleas post, or attach, the output of 'lvidpslay -v /dev/vg01/u01' (without the entire list of extents for the LV).

[Michal Kapalka (mikap)]

hi,

check this link from ITRC :

http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1260993774214+28353475&threadId=1070802

mikap

[Dave Chamberlin]

here is lvdisp info:
LV Name /dev/vg01/u01
VG Name /dev/vg01
LV Permission read/write
LV Status available/syncd
Mirror copies 0
Consistency Recovery MWC
Schedule striped
LV Size (Mbytes) 20480
Current LE 2560
Allocated PE 2560
Stripes 2
Stripe Size (Kbytes) 8
Bad block on
Allocation strict
IO Timeout (Seconds) default

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c4t0d1 1280 1280
/dev/dsk/c4t0d3 1280 1280

--- Logical extents ---
LE PV1 PE1 Status 1
00000 /dev/dsk/c4t0d1 00000 current

[James R. Ferguson]

Hi Dave:

> Stripes 2

This means you need _two_ physical volumes with free physical extents (half for each volume).

Regards!

...JRF...

[Vishu]

Hi Dave,

As you have a striped LV as Stripe=2, but your vgdisply does not show two PV having free PE available. So, you are getting above error.

You need to have two PVs with free PEs available in order to extend this LV.

[Dave Chamberlin]

As this is a virtual disk, how will I do that? I have two free luns, one in eac redundancy group. The first I used to extend vg01. I thought the VA was already using half the disks in the array for any given lun.

[Patrick Wallek · Accepted solution]

Your talking apples and oranges. LVM doesn't know or care what the VA is doing in the background.

What you are doing is striping your data across both RGs (assuming each disk used by the LV is in a different RG on the VA). This is efficient and makes use of both controllers and disks in each RG. The VA is then striping the writes to each LUN across all disks in the RG.

In order to extend your LV, you need to extend the VG by adding 2 LUNs from the VA. Each LUN can be 1/2 the size that you want to extend the LV by. Your lvextend should then work.