LVM and VxVM

Unable to mirror logical volume

 
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J.A.R. Karremans
Frequent Advisor

Unable to mirror logical volume

Hi everybody,

I am trying to mirror my increased logical volume using SAM.

Increased from 10G to 20G, reastablish mirror, it says:

The command used to extend logical volumes, /sbin/lvextend, has failed. The stderr output from the command is shown below. The logical volume has not been extended.

lvextend: Not enough free physical extents available. Logical volume "/dev/vg00/lvol10" could not be extended. Failure possibly caused by strict allocation policy.

What now??

I need my mirror...
13 REPLIES 13
Pete Randall
Outstanding Contributor

Re: Unable to mirror logical volume

We really need more information. It sounds like there isn't enough space to extend but the reason could be one of several. What was the exact command you issued? What does an "lvdisplay -v /dev/vg00/lvol10" show? What does a "vgdisplay -v /dev/vg00" show?


Pete

Pete
G. Vrijhoeven
Honored Contributor

Re: Unable to mirror logical volume

Hi,

Is the lvol striped? Did you use pvg's ?

Gideon
J.A.R. Karremans
Frequent Advisor

Re: Unable to mirror logical volume

Dear Pete,

Thanx for being so quick again!

Uploaded are both output's.

I find nothing strange about them. It just feels like it wants the mirror-copy to be contiguous on the mirror-disk, and it cannot do this. I don't want it either!!

Thanx,
Regards,
Jan
Robert-Jan Goossens
Honored Contributor

Re: Unable to mirror logical volume

Hi,

Like Pete said, there could be various reasons why you can not mirror the logical volume, below you will find a link to good doc from the itrc database.

http://www4.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000062683957

lvextend: Not enough free physical extents available DocId: KBAN00000084

Hope this helps,
Robert-Jan
john korterman
Honored Contributor

Re: Unable to mirror logical volume

Hi,
your logical volune already uses both disks in the volume group. Therefore you cannot mirror to a separate disk, which is what strict allocation policy requires.

regards,
John K,
it would be nice if you always got a second chance
J.A.R. Karremans
Frequent Advisor

Re: Unable to mirror logical volume

So...

I need to remove the second (mirror) disk from the lv-definitions and re-insert it?
With something like lvreduce orso?

Regards,
Jan
Pete Randall
Outstanding Contributor
Solution

Re: Unable to mirror logical volume

Jan,

Lvol10 already occupies both physical volumes, and there's no space left on one of them: /dev/dsk/c1t15d0. Without going through a very extensive rearrangement of your logical volumes, the only alternative I see is to change the allocation policy to non strict (lvchange -s n ), which pretty much eliminates any advantage of having the volume mirrored in the first place.


Pete

Pete
Jean-Louis Phelix
Honored Contributor

Re: Unable to mirror logical volume

Hi,

The basic problem is that you really don't have enough space to mirror such a big lv, even without strict policy. Your maximum possible size is 262+1976 PE = 17904Mo. Or same result with

Total PE 8680 = 69440Mo

Total used without lvol10 = 6704-2500 PE = 33632Mo

Available per mirror copy for lvol10 = (69440-33632)/2 = 17904 Mo

So 20000 Mo is too much in this vg.

Regards.
It works for me (© Bill McNAMARA ...)
Pete Randall
Outstanding Contributor

Re: Unable to mirror logical volume

Good point, Jean-Louis. I didn't even look at the total space. It just won't fit!!


Pete

Pete