lvextend a striped lvol

[Dan Copeland]

Admins,

I have a large logical volume (850GB) that I need to extend to 950GB. It is currently striped across 12 PV's (EMC metavolumes) -- we use LVM striping to stripe across the 12 PV's (lvcreate -i 12 -I 1024). I see that the lvol now has a strict allocation policy. This is preventing me from doing the lvextend to 950GB. Is there any way to extend this lvol w/o recreating. I tried lvchange -s n, but it states that striped lvols must be strict.

I understand the performance hit I will get by striping the first 850 GB across 12 PV's and putting the last 100GB on one PV. Not too concerned since it's a dev database...

Any suggestions?

tia,
Dan

[Shaikh Imran]

Hi,
What do you get from lvdisplay command whether it is strict or non-strict.
I suppose you can do it very well with
lvchange -s n /dev/vgXX/lvolX
If your lvchange command states that stripped lvols must be strict that means it not strict now. is it?
Its amazing that even if you have strict allocation policy configured and you lvchange is giving such a message.


Regs

[Victor BERRIDGE]

Hi,
I remember now why I never stripped on more than 4 disks...
To my knowledge if you lack of disk space, extending you lvol can only be done by adding another 12 disks... but what is stopping you to "extend" using/or by creating another file system and use a symbolic link somewhere?

All the best

Victor

[Cesare Salvioni]

There is no way to change the allocations policy with LVM, this is what the command is telling u when u try lvchange -s n.
When u create a striped LV u MUST distribute the stripes on a equal number of disks, otherwise striping is nonsense, so the only way to extend a striped LV is to have enough space on ALL the original physical disks.
Do not misunderstand the strict allocation policy with the contiguos allocation policy (yes or not)
The first one states that the stripes MUST be on different disks (strict) or different physical volume group, defined by /etc/lvmpvg (PVGSTRICT).
The second part decides if the extent must be contiguos or not.
If you defined the striped LV and then defined another LV u don't have extent contiguos to the first so the contiguos allocation is stopping u from extendig the first LV, but u can change this and go on even on a new bunch of disks.

Cesare

[Suresh Patoria]

Hi,

i am understanding u don't have enough free PE in ur volume group to extend the smae PV.
Create one more LUN and assign it to the target host. then extend the VG. then u try to extend the LV. pls don't extend the same LUN in EMC. create fresh LUN.

Thanx
Suresh P.