topic Re: bootable mirror in Operating System - HP-UX

bootable mirror

Geetam — Thu, 31 Aug 2000 13:07:36 GMT

Please point me in the right direction to create a bootable mirror of my root volume group. I want to be able to swap the mirrored disk to the place of the (faulty) boot disk.

1. I know how to create mirrored log vols, but do they have to be in the right place on the (second) disk?

2. What is the procedure to make the disk bootable?

Thanks

Re: bootable mirror

John Palmer — Thu, 31 Aug 2000 13:12:13 GMT

Hi,

A recent post in the HP9000 servers forum
http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0xcf860559ff7cd4118fef0090279cd0f9,00.html

Should give you the details.

Regards,
John

Re: bootable mirror

Victor BERRIDGE — Thu, 31 Aug 2000 13:12:14 GMT

pvcreate -B /dev/rdsk/cXd0s2
#mkboot -l /dev/rdsk/cXd0s2
#mkboot -a "hpux (;0)/stand/vmunix" /dev/rdsk/cXd0s2
then
#vgextend /dev/vg00 /dev/dsk/cXd0s2
then mirror all your lv in rootvg
#lvextend -m 1 /dev/vg00/lvol1 /dev/dsk/cXd0s2
#lvextend -m 1 /dev/vg00/lvol2 /dev/dsk/cXd0s2
etc...
Finally
#lvlnboot -r /dev/vg00/lvol1
#lvlnboot -s /dev/vg00/lvol2
#vgcfgbackup vg00

Re: bootable mirror

Victor BERRIDGE — Thu, 31 Aug 2000 13:15:07 GMT

If your disk is faulty, I would rather trust a restore form a good make_recovery tape on the 2nd disk rather than risking a complete failure during trying to mirror...

Re: bootable mirror

James R. Ferguson — Thu, 31 Aug 2000 13:18:02 GMT

Hi:

# pvcreate -B /dev/rdsk/cXtXdX
# vgextend /dev/vg00 /dev/dsk/cXtXdX
# mkboot /dev/rdsk/cX/tX/dX
# mkboot -a "hpux -lq /stand/vmunix" /dev/rdsk/cXtXdX
# lvextend -m # /dev/vg00/lvol1 /dev/dsk/cXtXdX
...etc...
# lvlnboot -v

Make sure use specify low-quorum (-lq) in the mkboot command. This way if your primary boot device fails, you can still come up!

...JRF...

Re: bootable mirror

Stefan Farrelly — Thu, 31 Aug 2000 13:43:32 GMT

I think an important point may have been missed here;

If youre intention is to create a bootable mirror disk, then physically remove the boot disk and replace it with the new mirror disk, then you system will NOT be bootable. The whole concept of using a mirrored disk is that the original disk must still connected to the system, at the same SCSI address/path, wether the disk be in use or a brand new blank disk (which you would then run vgcfgrestore on).

So, if this is what you intend to do then dont use mirroring. Instead use Ignite or shutdown your server to single user mode and dd the entire root disk to the mirror disk, then you can remove the boot disk, replace it with the new one you dd'd it to and you will be able to boot off it fine (without the old system/boot disk connected).
[eg. use dd if=/dev/rdsk/cxxxxx of=/dev/rdsk/cxxxxx bs=1024k]

Re: bootable mirror

CHRIS_ANORUO — Thu, 31 Aug 2000 13:55:32 GMT

Hi Geetam,

Stefan got straight to the point. I advise you backup your system before carrying out te changes. Use Ignite UX for proper recovery.

Chris

Re: bootable mirror

Lawrence Mahan — Thu, 31 Aug 2000 22:43:23 GMT

I did something similar on a test machine where I needed to run either HP-UX 10.20 or HP-UX 09.04. So I have two disk that where bootable. However I could not just move drives around and reboot. Instead I had to interrupt the boot and manually boot from the other drive. If you are trying to setup mirroring on the boot drive you will have the same problem as will.