extended striped logical volume to 2 new smaller disks?

[Mike Patterson]

I've been away from sys admin too long, so here is a problem and question: I'm working on a system running HP-UX 11.0. I have a VG currently built on 2 40GB LUNs in a disk array with 1 LV striped across these 2 disks (there is no unallocated space). I need more space in the LV, but I only have 2 25GB LUNs left in the disk array and strict allocation won't allow just adding 1 LUN. Question will strict allocation allow me to extend the LV across these 2 smaller LUNs in the VG or does it require 2 more 40GB LUNs?

[Patrick Wallek · Accepted solution]

Yes, you can extend the LV across the 2 25GB luns. As long as that 25GB provides you with enough space.

[V.Manoharan]

Hi mike ,
Since the existing VG is striped with two Physical disks it will expect to add disk in pairs to extend the LV doesn't matter the size of the LUN. Only you need to decide whether 25G is sufficient for your space requirement.

thanks and regards
V.Manoharan

[Sandman!]

The only restriction is that the VG needs to extended onto as many disks as are currently used by the lvol for striping. Assuming the VG is vg01, LV is lvol1 and the 2 new 25GB LUNs are c10t12d0 and c10t13d0 then:

# lvextend -L /dev/vg01/lvol1 /dev/dsk/c10t12d0 /dev/dsk/c10t13d0

[Mike Patterson]

Thanks guys, I know LVM commands, and I knew strict allocation requires that disks be added in multiples of the original set, but I just could not remember ever reading if they had to be the same size. - Mike