topic Re: Replace mirrored system disk with bigger disk in Operating System - HP-UX

Replace mirrored system disk with bigger disk

Geert Joosten — Fri, 10 Oct 2008 08:27:18 GMT

Hi,
We have a RX 2620 with HP-UX 11.23 and 2 internal disks size 72 GB, which are mirrored with MirrorDisk. Now we want to replace these disks with 2x144 GB. Is there a possibility to change mirror copies to 0, replace one disk and change mirror copies back to 1? Then the same action but now the replace the other 72 GB disk? Or is the only way using the recovery tape?
Thanks in advance,
Geert.

Re: Replace mirrored system disk with bigger disk

Ganesan R — Fri, 10 Oct 2008 08:33:36 GMT

Hi,

It is very much possible. As you said, reduce all the mirror copies from one disk and remove the disk from root VG.

Now connect the new 144GB disk and add it to root VG. Then extend the mirror to this new disk using standard mirror proceduce. Here you can reboot to check booting from new 144GB if you desire.

You need to follow the same procedure to replace the other 72GB.

Re: Replace mirrored system disk with bigger disk

sreekanthtm — Fri, 10 Oct 2008 08:37:10 GMT

Identify the primary and secondary disks
# lvlnboot -v

Break the mirroring
# lvreduce -m 0

Replace the secondary disk by new disk (144GB)
Mirror the new disk
# lvextend OR vgsync

Reboot the system using the new disk, and confirm its working...

Break the mirror again.
Replace the other 73GB disk.
Do mirroring again.............

But I would like to recommend to restore the OS from an ignite backup. its simple and less time consuming.

Best wishes
Sreekanth

Re: Replace mirrored system disk with bigger disk

James R. Ferguson — Fri, 10 Oct 2008 08:52:18 GMT

Hi Geert:

Merely mirroring the smaller to the larger disk may not benefit you. The original LVM geometry will be replicated from the smaller to the larger physical disk when you 'vgextend' it into the volume group. Thus your original 'pe_max', 'pe_size', etc. will be unaltered. You may or may not be able to utilize all of the larger storage.

Using Ignite in an Advanced Installation mode may be your best choice.

Regards!

...JRF...

Re: Replace mirrored system disk with bigger disk

Torsten. — Fri, 10 Oct 2008 17:45:01 GMT

If your VG limits doesn't fit to the larger disk (pe_max ...), you can still consider to use vgmodify to adjust them ...

An up-to-date system (running 11.23) should have vgmodify ...

Re: Replace mirrored system disk with bigger disk

Tim Nelson — Fri, 10 Oct 2008 18:08:02 GMT

As mentioned if pe_max does not stop you then you should be good to go.

Another option if vgmodify is not for you.

Create ignite image. replace one or both disks, reinstall OS.

Re: Replace mirrored system disk with bigger disk

Court Campbell — Fri, 10 Oct 2008 18:14:21 GMT

You should be able to do it and then use vgmodify to utilize the full pv. You will want to earmark this (man vgmodify):

The root/boot volume group must be booted into maintenance mode before making changes

Re: Replace mirrored system disk with bigger disk

Geert Joosten — Mon, 13 Oct 2008 08:32:45 GMT

Hello,
Considering the comments I go for the save way and use the Ignite-tape.
Thank you all.
Geert.