Mirrordisk/UX

[Sally Devine]

Hello;

Can Mirrordisk/UX mirror between two disks of different sizes? Like can I mirror the volumes of a 2GB disk onto a 9GB? I figured that I could, but I just wanted to make sure.

Thank you,
SD

[Pete Randall · Accepted solution]

Sally,

Mirroring is done on a logical volume basis so as long as the two disks are in the same volume group it makes no difference.

Pete

[Ben Sachs_1]

I'm Jumping on this one early, but the answer is, yes.

Because Mirrordisk/UX will mirror volumes and does not care about disk size.

So if you have 2gb worth of lvols that you want to mirror onto the 9gb drive, it is not a problem. You will just have extra space on the 9gb drive.

-Ben

[Ken Hubnik_2]

You mirror by logical volume so yes it would work but if you use the rest of the 9GB space for something else then you could not just replace the 9GB drive in a failure since only 2gbs is mirrored.

[James R. Ferguson]

Hi Sally:

Yes, you can. Mirroring for LVM is implemented at the logical volume level.

However, this uncovers the fact thay you have probably added (or want to add) a 9GB physical volume to a 2GB existing one. If you do this, and no provision was made for specifying 'max_pe' during the 'vgcreate' of the 2GB disk, then you will limit the availability of physical extents on the 9GB disk to the maximum number on the 2GB disk, thereby *wasting* a valueable amount of space.

Regards!

...JRF...

Regards!

...JRF...