System Administration
cancel
Showing results for 
Search instead for 
Did you mean: 

Do mirrored drives (Mirrox UX) need to be same size ?

Sammy_2
Super Advisor

Do mirrored drives (Mirrox UX) need to be same size ?

I need to lvextend -m 1 all lvs from one disk OLD PV to another (NEW PV).

OLD PV size=100g, Alloted space to LVs total is 25gb
NEW PV size =50gb

Can I still mirror from OLD PV to NEW PV since the allocted space (Aloocated PE in vgdisplay X 4) is less than 50gb ?

Thanks
good judgement comes from experience and experience comes from bad judgement.
3 REPLIES
Hasan Atasoy
Honored Contributor

Re: Do mirrored drives (Mirrox UX) need to be same size ?

hi ;

it is clear that you have unallocated space in the original disk , you can use the new disk. you will just less free space in the new disk.


Hasan.
Kapil Jha
Honored Contributor

Re: Do mirrored drives (Mirrox UX) need to be same size ?

Yes you can mirror it.....but ideally should be same on both disks for future reference...if LV size increases after 50GB it would create the problem.

BR,
Kapil+
I am in this small bowl, I wane see the real world......
James R. Ferguson
Acclaimed Contributor

Re: Do mirrored drives (Mirrox UX) need to be same size ?

Hi Sammy:

LVM mirroring is done at the logical volume level, not the physical volume nor the filesystem. Hence, you must have an equal number of free physical extents available on the physical volume on which the mirror will be created.

The other constraint is that no mirrored extent should share the same physical volume. This is enforced by default and is called "strict allocation". See the 'lvcreate' manpages for more information.

In your case, as long as these caveats are met it doesn't matter that your new physical volume is smaller than your old physical volume, given your data.

Regards!

...JRF...