Disk mirroing

[Raghuram Ollakal_1]

I install a Sure Store Disk system with 4 X18 GB HD on one of my HP 9000 K-class server. Now I am trying to convert my file system to use the new HD. I create a recovery tape ( make_tape_recovery) to restore the file system. When I was checking the current logical volumes I noticed that - the " / , /home, /opt, /tmp, /us and /var shows under Mirror Copies " 1". When I boot the system with my recovery tape and came to the menu, I am not able to see an option for mirroring, I can add disk, and change the size of the volumes etc. My question is where can I change the mirroring. Please hel

[Darrell Allen]

Hi,

When loading a system from an Ignite backup, you do not have the capability to mirror. After installation, boot up the system and mirror your LVs at that point.

Darrell

[James R. Ferguson]

Hi:

If you use Ignite to restore a system, as from a 'make_tape_recovery', you need to manually (via a script, or otherwise) remirror your logical volumes.

Regards!

...JRF...

[Sanjay_6]

Hi,

you have to redo the mirroring part manually. Or you can configure as a post install option in your ignite custom installation script.

Take a look at this doc,

http://www.software.hp.com/products/IUX/docs/diskmirror.pdf

Hope this helps.

regds

[Jeff Schussele]

Raghuram,

You'll need to extend the VG first
#vgextend /dev/vgXX /dev/dsk/cXtXdX

Then extend the LV with the mirror :
#lvextend -m 1 /dev/vgXX/lvXX /dev/dsk/cXtXdX

HTH,
Jeff

[Raghuram Ollakal_1]

I checked the doc. I just want to confirm one thing. If my present configuration is a mirrored, and still I can use the ignite to create amake _tape_recovery. but it will not preserve the mirror configurations.and after booting from the system recovery tape, disk mirrors will be lost. Do I have to reeconfigur the system to a mirrored. or can I live it without mirriing the disk?

ttp://www.software.hp.com/products/IUX/docs/diskmirror.pdf

[Jeff Schussele]

Only if you can live with the downtime if you lose a disk.

I'd mirror it - unless you absolutely HAVE to use the disk space for something else.

Jeff

[Sandip Ghosh]

I think it is always better to redo the mirroring of the vg00. Because if anything happens to the root disk you can always boot through the mirror disk.

Sandip

[Helen French]

Hi Raghuram,

From the man pages of make_recovery:

## LVM Disk Mirrors not Restored
The make_recovery tool will create a recovery tape for a system with mirrored disks but it will not restore the mirrored disk configuration. If the system is later recovered, previously mirrored volumes will no longer be mirrored. They can be manually re-mirrored after the system is up. Using make_recovery -p allows appending commands to restore mirrored disks to be executed automatically after the system has been restored. For more details, see the white paper - /opt/ignite/share/doc/diskmirror.pdf.

### end quote

I think this clarifies you. See man pages for more details.

HTH,
Shiju

[Darrell Allen]

Hi,

The answer is it depends. Is this a production system? Does it matter that a boot disk crash will bring down the system? If it doesn't matter and you are short on disk space, then you don't have to use mirroring.

Personally, I'd mirror it.

Darrell

[Helen French]

Hi,

Again, it is always good and safe to have the root disk mirrored. You can reduce the system down time when you have this. The steps are very simple and easy. I would recommend you to do this after the recovery process.

HTH,
Shiju