topic Mirror a common Disk in Operating System - HP-UX

Mirror a common Disk

Gustavo Souza Lima — Mon, 16 Jul 2007 07:30:56 GMT

Hi...I have a L2000 server with 4 disk's and on this last weekend I've tried to set up MirrorDisk/UX. In the first disk is with the operating system HPUX 11.00 and I can to set up the mirror on the second disk successfully.
In the third disk there is the application and I've attempted to set up mirror on the fourth disk, but when I taked off the third disk to test the mirror, I couldn't mount the logical volumes of the application. Follow the commands that I've executed:

1 - pvcreate -f /dev/rdsk/cXtYdZ (fourth disk)
2 - vgextend /dev/vg01 /dev/dsk/cXtYdZ
3 - for lv in 10 11 12
>do
>lvextend -m 1 /dev/vg01/lvol$lv /dev/dsk/cXtYdZ
>done
4 - vgcfgbackup /dev/vg01

All commands were completed successfully.

Please Help me!!!

Re: Mirror a common Disk

Mridul Shrivastava — Mon, 16 Jul 2007 07:34:59 GMT

in LVM we can get only 2 way mirror, means max 2 disk u can mirror with one so u can not add the 3rd mirror.
If you want to have multiple mirror then go for Vxvm

Re: Mirror a common Disk

Steven E. Protter — Mon, 16 Jul 2007 07:35:31 GMT

Shalom,

You don't mirror a disk.

You mirror a logical volume.

example
lvol2 (part of vg01)

lvextend -m 1 /dev/vg02/lvol2 /dev/dsk/c1t2d1

Now its mirrored.

You don't have to umount, you don't have to remount. You don't change /etc/fstab. You are done.

SEP

Re: Mirror a common Disk

Torsten. — Mon, 16 Jul 2007 07:35:56 GMT

I assume you could not mount because you can't activate the volume group?

Did you use the quorum mode?
You have to do this, because your VG01 has <=50% off all disks.

Re: Mirror a common Disk

Ninad_1 — Mon, 16 Jul 2007 07:36:07 GMT

Is the vg01 still active ?
It may so have happened that since you have only 2 disks in the vg01 out of which after you removed one disk, the quorum was not met for the vg01 and hence it was deactivated - if so you can activate it using vgchange -q n /dev/vg01
and then try mounting the volumes after doing a fsck first.

Regards,
Ninad

Re: Mirror a common Disk

Gustavo Souza Lima — Mon, 16 Jul 2007 08:00:07 GMT

Hi Ninad,

I think that your solution can solve my problem....I will try to use this command and then I will post the solution and give your points...

Thank you!!!!
Gustavo

Re: Mirror a common Disk

Torsten. — Mon, 16 Jul 2007 08:06:37 GMT

If the vg01 is still active the removal of the disk won't turn it to de-activated.
But if you shutdown your system, remove the disk and boot, the vg will not be activated without the quorum override setting.

You can force this by booting

ISL> hpux -lq

or use the vgchange command later as mentioned above.

Re: Mirror a common Disk

Timothy P. Jackson — Mon, 16 Jul 2007 21:12:22 GMT

Hey Gustavo,

Hopefully you have found your issue with help of the previous responses. If not take a look at this document. It is a great reference guide! Every once in a while I will screw something up and I take a quick look at this to help me figure out what I did or didn't do.

http://docs.hp.com/en/5991-1236/When_Good_Disks_Go_Bad.pdf

Re: Mirror a common Disk

Gustavo Souza Lima — Sun, 22 Jul 2007 14:59:55 GMT

Thanks Ninad...
Your solution solved my problem...

But I still have a question..
I have two disk in Mirror and suppose that the Main Disk has failed and I start using the mirror disk...My question is..when I replace the Bad Disk for a Good Disk what I need to do to synchronize the disks??

Re: Mirror a common Disk

Torsten. — Mon, 23 Jul 2007 01:29:25 GMT

Your solution is in this document (as already mentioned above):

http://docs.hp.com/en/5991-1236/When_Good_Disks_Go_Bad.pdf

Re: Mirror a common Disk

Gustavo Souza Lima — Mon, 23 Jul 2007 08:29:11 GMT

vgchange -a y -q n /dev/vgXX

The flag -q disable the quorum verification to active a vg.