How can I remove a disk from a group with striped volumes?

Question

I have an HP-UX B.11.11 system with two disks. I would like to remove one, but as far as I can divine, it seems that the volumes are striped across the pair and I can't figure out how to convert/move/reduce the data so I can remove a pv.

# pvdisplay /dev/dsk/c3t6d0
--- Physical volumes ---
PV Name                     /dev/dsk/c3t6d0
VG Name                     /dev/vg00
PV Status                   available                
Allocatable                 yes          
VGDA                        2   
Cur LV                      5      
PE Size (Mbytes)            8               
Total PE                    4340    
Free PE                     3742    
Allocated PE                598         
Stale PE                    0       
IO Timeout (Seconds)        default             
Autoswitch                  On        

# vgreduce vg00 /dev/dsk/c3t6d0
vgreduce: Physical volume "/dev/dsk/c3t6d0" could not be removed since some of its
physical extents are still in use.
# pvmove /dev/dsk/c3t6d0
Operation cannot be performed because some of the data on the physical volume
is striped and striped mirroring is not supported. To enable data transfer for
a physical volume through mirroring/reduction, do not specify the striping
options (-i, -I) when creating logical volumes on that physical volume.

Has the striping been an irreversible choice?

Answer 1

If you want to take one disk off the volume group from the current state, then your LVM setup being striped, it is not possible.

But then, you probably won't have to migrate the whole system, but you can create a mirror of the existing stripped volume which will eventually help you take that one disk off from your setup.

A few months back I had created a mirror(which is linear) of one of my stripped LVMs. I had used the steps provided in this link that time and it had all gone smooth. Once you have the mirror this way, remove the disks that hosts the striped volume. I suggest you go through the steps there.

P.S: There are also people talking about creating a clone of the current disk with dd. And replacing the old disk with the new one. I haven't tried this, but you can research along these lines too, but I believe there will be additional steps you need to perform to be able to use that 'clone'd disk.

Answer 2

I think you should first analyze the content of that disk with:

# pvdisplay -v /dev/dsk/c3t6d0 | grep current | awk '{ print $3 }' | sort -u

That will give you a list of logical volumes

Then analyze how those volumes are stored with

# lvdisplay -v <lvol>

With that data you can take decisions. For instance, is there is only one logical volume in the disk, and that volume can be unmounted, you have the choice to move its content to another, new, non striped logical volume.

The answer in fact is: striping is irreversible. But after some investigation, you can find a solution and remove the disk.