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Mirror Disk Help

Steven Chen_1
Super Advisor

Mirror Disk Help


I would like to know how to add the mirror for root drive that I don't have at all.

Any card, action etc. do I need to prepare?



A. Clay Stephenson
Acclaimed Contributor

Re: Mirror Disk Help

Hi Steven,

Since you don't mention your hardware, I'll speak in general terms. To do this correctly,
you need to protect your self from more than simply a disk failure. You need to be able to tolerate a controller failure or a cable failure (or accidental disconnection) as well.

I'll use a D-3xx box with internal hot-plug drives as an example. Let's say you are booting from a 4GB disk on the internal HVD SCSI drive. To mirror correctly, you need to
have an external drive enclosure (e.g. a Jamaica), a second HVD SCSI controller, a second (ideally) identical 4GB drive, cables, and terminator(s). You of course also must install the Mirror/UX software.

This fully protects and mirrors your data.
If possible, avoid internal disks which are not
hot-pluggable. For example, none of my K-box use internal drives instead I boot from external drives - this way I can replace a drive without shutting down the box.

You can, of course, simply put in a second drive (with a different SCSI ID) on your current bus but that only protects from a drive failure.

Once the hardware is configured, the actual mirroring is simple.

Regards, Clay
If it ain't broke, I can fix that.
Michael Tully
Honored Contributor

Re: Mirror Disk Help

Hi Steven,

Clay's suggestion in addressing the hardware
issues are perfect.

I have a script here slightly different with
a little less typing to do the logical volume

# pvcreate -f -B /dev/rdsk/cXtXdX
# vgextend /dev/vg00 /dev/rdsk/cXtXdX
# mkboot /dev/rdsk/cXtXdX
# mkboot -a "hpux -lq(;0)/stand/vmunix" /dev/rdsk/cXtXdX
# lvlnboot -R
# for LVOL in /dev/vg00/lv*
> do
> echo $LVOL
> lvextend -m 1 $LVOL
> done

One other suggestion is to do a make_recovery tape on completion. This will ensure that you have an operating system of your system on a bootable tape.
we use this procedure.

# make_tape_recovery -x inc_entire=vg00 -I -v -a /dev/rmt/0mn
(assuming /dev/rmt/0m is you DDS tape drive)


Anyone for a Mutiny ?
Honored Contributor

Re: Mirror Disk Help

Hi Steven,

You might want look at chapter 7 in http://docs.hp.com/hpux/pdf/B2355-90672.pdf


You will get more information about guidelines for setting/managing LVM mirrors.

I am RU
They think they know but don't. At least I know I don't know - Socrates