Mirror a common Disk

 
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Gustavo Souza Lima
Frequent Advisor

Mirror a common Disk

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!!!
10 REPLIES 10
Mridul Shrivastava
Honored Contributor

Re: Mirror a common Disk

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
Time has a wonderful way of weeding out the trivial
Steven E. Protter
Exalted Contributor

Re: Mirror a common Disk

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
Steven E Protter
Owner of ISN Corporation
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Torsten.
Acclaimed Contributor

Re: Mirror a common Disk

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.

Hope this helps!
Regards
Torsten.

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Ninad_1
Honored Contributor
Solution

Re: Mirror a common Disk

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
Gustavo Souza Lima
Frequent Advisor

Re: Mirror a common Disk

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
Torsten.
Acclaimed Contributor

Re: Mirror a common Disk

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.

Hope this helps!
Regards
Torsten.

__________________________________________________
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those who understand binary, and those who don't.

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Timothy P. Jackson
Valued Contributor

Re: Mirror a common Disk

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
Gustavo Souza Lima
Frequent Advisor

Re: Mirror a common Disk

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??

Torsten.
Acclaimed Contributor

Re: Mirror a common Disk

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

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

Hope this helps!
Regards
Torsten.

__________________________________________________
There are only 10 types of people in the world -
those who understand binary, and those who don't.

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No support by private messages. Please ask the forum!

If you feel this was helpful please click the KUDOS! thumb below!