can't extend to 90G : lvextend

[j773303]

OS: 11.11 / superdome
DiskArray: XP
filesystem: assume "/dev/bilapvg/event_file"

lvdisplay "/dev/bilapvg/event_file"
PE: 16M
Stripe(s): 4
Allocationpolicy: Strict

------------------------------------------
"/dev/bilapvg/event_file" 25G currently.
I'd like to extend to 90G.

Try to extend a filesystem. But I meet a very strange problem, It failed extend to 90G. Please view the below results, I'm sure the disk space is enough to extend to 90G. However, it is OK to extend to 92G.

Does anyone has any advice to explain such this stange problem? Many Thanks !!




bils01p:/#lvextend -L 92160 /dev/bilapvg/event_file

lvextend: Not enough free physical extents available.

Logical volume "/dev/bilapvg/event_file" could not be extended.

lvextend: Couldn't retrieve the list of the physical volumes

belonging to volume group "/dev/bilapvg".

Failure possibly caused by strict allocation policy

bils01p:/#lvextend -L 61440 /dev/bilapvg/event_file

Logical volume "/dev/bilapvg/event_file" has been successfully extended.

Volume Group configuration for /dev/bilapvg has been saved in /etc/lvmconf/bilap

vg.conf

bils01p:/#lvextend -L 81920 /dev/bilapvg/event_file

Logical volume "/dev/bilapvg/event_file" has been successfully extended.

Volume Group configuration for /dev/bilapvg has been saved in /etc/lvmconf/bilap

vg.conf

bils01p:/#lvextend -L 94208 /dev/bilapvg/event_file

Logical volume "/dev/bilapvg/event_file" has been successfully extended.

Volume Group configuration for /dev/bilapvg has been saved in /etc/lvmconf/bilap

vg.conf

[Steven E. Protter · Accepted solution]

Shalom,

Your volume group itself does not have enough extents available for these disks.

Unless told otherwise, the volume group configuration at create time plans for the ability to spread available extents over 255 disks.

That may be realistic for some folks, but not anyone I know.

So what is needed is to set a realistic limit of the number of disks for this volume group and recreate it.

Without fear of damage (still backup first) you can vgexport the volume group and re-create it.

If you think you'll never have more than a say 10 disks in the group, then set a phyiscal volume limit of say 20.

-p 20

Along with the rest of your vgcreate parameters.

Suddenly you'll be able to extend to the size you wish.

SEP

[j773303]

Hi Steven,
Thanks for your quickly reponse.

I'm confused that volume group itself have enough extents available. Because it can be extend to 50G or 80G or 92G, but ONLY failed in 90G.

I don't belive this is a BUG of LVM. May be something wrong in my understanding. Please someone give me any other advice or suggestion and help me clarify the problem.

[john korterman]

Hi,

a simple explanation could be that at the very moment you tried to extend to 92160, LVM could not access any of the physical disks - the error:

Couldn't retrieve the list of the physical volumes belonging to volume group "/dev/bilapvg".

indicates this and therefore extension fails.

During the following attemps the disks were avialable.

Is that plausible?


regards,
John K.

[Senthil Kumar .A_1]

Hi,

Can you let us know the stripe size, you have enployed, or is it just "extent stripe".

can you give us the following outputs.

vgdisplay -v /dev/bilapvg
lvdisplay -v /dev/bilapvg/event_file | head -150

Please attach the output instead of pasting driectly in the post.

Regards,
Senthil Kumar .A

[j773303]

Dear Expert,
Attached please view the lv and vg details information. Currently, It is extend to 92G. Please help me identify the problem why can't extend to 90G.

Thanks

[Senthil Kumar .A_1]

Hi,

Since you already have extend it to "92G", Please perform this small harmless test. Try reducing the said LV to "90G". Lets see what happens. May be we can come to a certain conclusion based on the result. But be sure to revert back by extending back.

The test sequence is...

lvreduce -L 92160 /dev/bilapvg/event_file
lvdisplay -v /dev/bilapvg/event_file | head -150
lvextend -L 94208 /dev/bilapvg/event_file

Please attach the output of the above commands for analysis.

Regards,
Senthil Kumar .A