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should raw root/boot copy go on internal or external disk?

 
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Paul Senior_1
Frequent Advisor

should raw root/boot copy go on internal or external disk?

I am upgrading an alk370 machine.
It has 1x2gb internal disk and, when finished, will have 2x hass/jamaica external disk arrays with 8x9gb disks in each + mirroring on 2 separate buses.

As I want maximum cover on this machine, I intend to use dd to do a raw copy of the boot/root internal disk. The question is - should this copy go on an external disk or another internal disk (what are the pro's and cons of each?).

A separate question also - is it advisable to mirror the root disk AS WELL as creating a raw copy of the root/boot disk?
4 REPLIES 4
Mark Nieuwboer
Esteemed Contributor
Solution

Re: should raw root/boot copy go on internal or external disk?

hi Paul,

If you do a raw copy of the disk you can't use it.
Because there are more steps to make to make a disk bootable.
Second i prevere internal disk because when your external disk are gone by some reason.
(cable failere our disk failure) you want see that on the system. How ever you can make a mirror on the extarnel disk this way you are sure that either way you have a bootdisk.
To make a mirror bootdisk on a 32 bit HPUX do:

pvcreate -f -B /dev/rdsk/
vgextend /dev/vg00 /dev/dsk/
mkboot /dev/rdsk/
mkboot -a "hpux -lq (;0)/stand/vmunix" /dev/rdsk/
mkboot -b /usr/sbin/diag/lif/updatediaglif -p ISL -p AUTO -p HPUX -p PAD -p LABEL /dev/rdsk/

to mirror the logical volumes i use:
for i in 1 2 3 4 5 6 7 8
do
lvextend -m 1 /dev/vg00/lvol$i
done

good luck
Mark
Robert-Jan Goossens
Honored Contributor

Re: should raw root/boot copy go on internal or external disk?

Paul,

I think you will have an other problem.

# vgdisplay -v vg00
check the size of the "Max PE per PV" and the "PE size" parameters.

If you are going to upgrade your internal (VG00) disk, this will be a depending factor.

You could use a make_tape_recovery, and install your system to larger disks.

Hope this helps,
Robert-Jan
Paul Senior_1
Frequent Advisor

Re: should raw root/boot copy go on internal or external disk?

My plan is now the following:-

place root/boot disk on external array. Mirror the root/boot disk in the external array, but on the other HASS scsi bus.
put a raw copy of the root/boot disk on the internal disk and keep it refreshed every few weeks.

This will give me protection from failure, although will there be potential performance problems?
- I intend to put the boot disk in one of A1,A2,B1,B2 slots as these spin up first and syncronously, and give it the highest SCSI device number on the bus (6).
I assume the overheads from mirroring will not be significant and that there is no difference in performance between an internal & external disk?
Mark Nieuwboer
Esteemed Contributor

Re: should raw root/boot copy go on internal or external disk?

You can't place a root disk in a extarnal array and then boot from it. The kernel whil not recognice the disk.
Make an ignite images of your current server.
Then ignite it on a extarnal disk.
After this you can make a mirror as explaned.
Don't do a raw boot/copy that will not help if you have a disaster.

grtz. Mark