Re: [linux-lvm] Best way to image devices in an LVM environment

[Andy Smith <andy@strugglers.net>]

[-- Attachment #1: Type: text/plain, Size: 2301 bytes --]

On Sun, Aug 27, 2006 at 07:51:09AM -0400, Matthew Gillen wrote:
> Andy Smith wrote:
> > On Sun, Aug 27, 2006 at 01:20:26PM +0800, Jim Morgan wrote:
> >> Basically you have to force one disk to fail using the raid 
> >> administration software. You then remove the disk, replace it with 
> >> the bigger disk, and rebuild it from the first one. The partition 
> >> sizes may need adjusting. Then you force the other disk to fail, and 
> >> replace it with the larger one, and then rebuild it from the other large 
> >> disk.
> > 
> > Well I would then be left with two large disks where sd[ab]5 (and
> > the sd[ab]4 primary partition that sd[ab]5 is the only logical
> > partition within) does not extend all the way to the end of the
> > disk.  I wasn't aware that you could resize RAID-1 md arrays though,
> > I thought it was restricted to RAID-5.  Is this not the case?
> 
> To add another "I'm not an expert" opinion:
> Supposing you can get all 4 disks in the server at the same time,

I can't; it's a rackmount server with only two disk bays and two
SATA ports on the motherboard.  I could have it open with another
2-port SATA controller on a PCI card, but this seems to be going a
bit far.

Since I only want to give the extra space to the single volume group
then it seems I should be able to follow this method:

http://www.debian-administration.org/articles/424

(basically involves doing what Jim said: failing out one disk,
replacing it with a bigger one, failing the other, replacing it,
then expanding partitions and filesystems.)

Seems that "mdadm --grow" works even with a RAID-1 which I wasn't
aware of.

The only problem then remaining would be how would I grow the single
pv/vg out to the full extent of the new larger block device it would
be on.  There doesn't seem to be a pvresize in Debain Sarge's lvm2
package..

  LVM version:     2.01.04 (2005-02-09)
  Library version: 1.01.00-ioctl (2005-01-17)
  Driver version:  4.5.0

I see from:

http://www.robot101.net/2005/05/20/resizing-lvm2-physical-volumes/

that lvm2 has had pvresize since 2.02.00 so if I upgrade userland
tools (my kernel is 2.6.16.19) then would I just need to do a
pvresize after expanding the block device that my single pv/vg is
on?

Cheers,
Andy

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 189 bytes --]