lvextend error!

[Hell.Leader]

Hi all, I can not run lvextend , here is my situation:
-------------------------------
1)One 18GB HD; The second 18 GB HD is used as mirror;
2)#vgdisplay vg00
...
PE Size(M bytes) 4
Total PE 8680
Alloc PE 7616
Free PE 1064
...
3)#bdf
...
/dev/vg00/mfg1 3481600 3048384 406154 88% /mfg1
...
4)#lvextend -L 4000 /dev/vg00/mfg1
lvextend: Not enough free physical extents available.
Logical volume "/dev/vg00/mfg1" could not be extended.
Failure possibly caused by strict allocation policy.

-----------------------------------
What's the matter? How to deal with it?
TKS.

Leader.

[Steven Sim Kok Leong · Accepted solution]

Hi,

Your /dev/vg00/mfg1 was lvcreated with a strict allocation policy which prevents the mirror copy of this LV from sharing the same physical disk with the LV. If an LV uses physical extents that reside on the same physical disk as its mirror copy, a failure of either one of the 18 GB disks will render both the LV and the mirror copy useless.

When you perform a vgdisplay, the total free PEs include those on both disks. You should thus acquire more harddisks for your storage requirements.

If you urgently need space, you can workaround this by disabling the strict allocation policy via

# vgchange -s n /dev/vg00/mfg1

However, NOTE that this will render your mirror useless and thus should only be used as a last and temporary resort to resolve urgent space requirements.

Hope this helps. Regards.

Steven Sim Kok Leong