lvm root mirror

[Brian Street_1]

Hello,

I don't think my attempt at mirroring my root disk worked. Is there a way to back out of it now and start all over without reinstalling the OS?

I have an N4000 running 11.11. Here is the output of the lvlnboot -v command:
Boot Definitions for Volume Group /dev/vg00:
Physical Volumes belonging in Root Volume Group:
/dev/dsk/c2t6d0 (0/0/2/1.6.0) -- Boot Disk
/dev/dsk/c1t6d0 (0/0/2/0.6.0)
Boot: lvol1 on: /dev/dsk/c2t6d0
Root: lvol3 on: /dev/dsk/c2t6d0
Swap: lvol2 on: /dev/dsk/c2t6d0
/dev/dsk/c1t6d0
Dump: lvol2 on: /dev/dsk/c2t6d0, 0

When I was trying to extend the logical volumes to the second disk I was constantly getting the error message that to run the mkboot command, even after I ran it each time.

Thanks for your help,
Brian Street.

[James A. Donovan · Accepted solution]

Sounds like you forgot to use the "-B" option with the pvcreate command.

To back out:

First run "lvreduce -m 0" to remove on mirrors you may have already created, then

# vgreduce vg00 /dev/dsk/c1t6d0
# pvcreate -f -B /dev/dsk/c1t6d0

then rebuild your mirrored boot disk

Here's a link to detailed instructions
http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000066581345

[James A. Donovan]

Sounds like you forgot to use the "-B" option with the pvcreate command.

To back out:

First run "lvreduce -m 0" to remove on mirrors you may have already created, then

# vgreduce vg00 /dev/dsk/c1t6d0
# pvcreate -f -B /dev/dsk/c1t6d0

then rebuild your mirrored boot disk

Here's a link to detailed instructions
http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000066581345

[Brian Street_1]

So, forgive me for sounding ignorant, but do I have to have mirrordisk installed to make this work?

Thanks,
Brian Street.

[Balaji N]

hi,
yes. u need to HP Mirror Disk software installed for mirroring to work.
check out the man pages.

hth
-balaji

[Armin Feller]

Hi Brian,

you can remove the disk /dev/dsk/c1t6d0 from vg00 without having MirrorDisk/UX and you can also make the disk bootable using:

# pvcreate -f -B /dev/rdsk/c1t6d0

but to mirror your root disk (or any other disk) you have to have MirrorDisk/UX installed before.

Regards ...
Armin

[James A. Donovan]

If you want only a bootable disk then no, you do not need the Mirror-U/X product. You can create a bootable disk using the instructions given in that link.

here's a couple of other threads on mirroring without Mirror-U/X. You'll have to maintain the mirrors manually...

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xafc36af52b04d5118fef0090279cd0f9,00.html

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x37204b3ef09fd611abdb0090277a778c,00.html

[Brian Street_1]

In response to the reply from Jim, I followed the procedure and everything appeared to go smoothly. However, when I rebooted from the alternate path to test the mirrored disk I received disk not ready and retrying disk errors.

It looks like the mkboot command didn't work to make the disk bootable; is that right?

Thank you,
Brian Street.

[Sridhar Bhaskarla]

Hi Brian,

Disk not ready message indicates that it is unable to access the drive. At the boot admin prompt, run the following command and see if it lists the alternate disk as a bootable disk

sea ipl

-Sri

[Brian Street_1]

Sridhar,

Shouldn't I be concerned that I have a problem if the disk was seen on the previous boot but now it can't see it? I'm rebooting to run the search command now, but that would seem pretty strange to me since it was there and I was able to install the mirrors, etc.

Brian Street.

[James A. Donovan]

What do you see if you run:

# lifls -l /dev/rdsk/c1t6d0

At a minimum, you must have AUTO, ISL, and HPUX

What are the contents of the AUTO file?

# lifcp /dev/rdsk/c1t6d0:AUTO -

[Sridhar Bhaskarla]

Hi Brian,

I was trying to make sure your alternate path is setup correctly. It should correspond to the path to your alternate disk.

Once you run sea ipl, it will show all the boot disks so you should be able to figure it out.

If you see only one disk as bootable (primary), then simply do "sea" to see if that mirror disk is physically present or not.

You can be unlucky sometimes. It's mere hardware.

-Sri

[Brian Street_1]

Sridhar,

The disk was seen when I ran the search command and is booting up now.

So, should I have to search for the boot devices each time before I give the boot command? So, I'm leaning toward an intermittent problem with my system.

Thank you,
Brian Street.

[Brian Street_1]

Hello everyone,

Everything appears to be working normally. I can boot from my mirror without any errors.

Jim, I checked the files and they all contained the appropriate information entered during the procedure you gave me.

Thank you all,
Brian Street.

[Sridhar Bhaskarla]

HI Brian,

You do not need to a 'sea' everytime you boot the box.

Check the PDC and firmware on the server. If they are ok, then try booting the box couple of times to see if it boots without manual intervention. If not, it could be an intermittent problem and may have to reseat the disk.

-Sri