mirroring

[Keith Floyd]

Hi

I have a 9GB disk (O/S) I want to change this to 18GB and then mirror another 18GB

Is this the correct way

mirror the 9 onto the 18 (inc lvlnboot)
remove the 9 and replace with the 18 and remirror 18 -18

Thanks

Keith

[Stefan Farrelly · Accepted solution]

Your procedure will only work if you can successfully add in the 18Gb disk to Vg00 without getting an error about not enough extents. The problem is vg00 now with a 9Gb disk has the MAX PE per PV set to 9gb/4, whereas for an 18Gb disk you will need 18Gb/4. Try adding in the 18Gb disk to vg00, if you dont get an error and a vgdisplay on vg00 shows MAX PE per PV at around 4500 then yes, your procedure will work. If not, you will have to use ignite to offload vg00 to tape, boot off the tape and restore it to the 18Gb disk.

[John Palmer]

It would work provided that your root volume group was originally created with a Max Physical Extents per Physical Volume (Max PE per PV - check with 'vgdisplay vg00'. This is unlikely however and you will probably find that this is set to 2500 or less giving you a maximum amount of space that can be allocated of about 10Gb or less.

If Max PE per PV is too small then you will have to go through an exercise of creating a new root disk on the 18Gb disk and then importing the rest of your volume groups.

The considered opinion on the forum is to use the free Ignite package in order to do this but you can setup the 18Gb as a new boot disk and copy over your existing root volumes.

A search of previous posts will reveal a lot of information on this subject.

Regards,
John

[Andreas Voss]

Hi,

for your job i think you have to use ignite.
Let me explain:
In the time of creating the volume group (i assume vg00 because you said OS is on it)
the value of Max PE per PV (can be seen with vgdisplay vg00) is set to the biggest disk within the vg. I'm very sure that your vg00 has only Max PE for a 8 GB disk.
So you cannot add a 18GB disk into vg00 and use the full capacity.

So you have to backup with ignite your vg00, replace the disks, reinstall fom tape and setup mirroring.

Regards

Andrew

[Dave Wherry]

I agree with the 3 previous posts and to summarize them,
Create a make_recovery tape. Make sure you download the latest ignite package and use that. Simply install it and then create the tape.
Down your system and replace your 9GB drives with your 18GB.
Boot and interupt the boot. Tell it to boot off of the tape. You can then resize volume group and logical volume sizes.
It really is very easy and safe. I would guess it may take you 3 to 4 hours. Not too bad at all.