topic Re: Disk replace (no mirror) in Operating System - HP-UX

Disk replace (no mirror)

Anton Yatsun — Tue, 17 Feb 2009 10:34:44 GMT

Hi, gentlemens

I have two 146G SCSI disks in rx2620.
They are create one vg00:

vgdisplay -v vg00
--- Volume groups ---
VG Name /dev/vg00
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 12
Open LV 12
Max PV 16
Cur PV 2
Act PV 2
Max PE per PV 4356
VGDA 4
PE Size (Mbytes) 32
Total PE 8692
Alloc PE 8692
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
{skipped}
--- Physical volumes ---
PV Name /dev/dsk/c2t0d0s2
PV Status available
Total PE 4346
Free PE 0
Autoswitch On

PV Name /dev/dsk/c3t2d0s2
PV Status available
Total PE 4346
Free PE 0
Autoswitch On

One of the disks (c2) starts to have I/O errors and should be replaced by new one.

What ways can recommend to do that?

Thanks in advance.

Re: Disk replace (no mirror)

Jeeshan — Tue, 17 Feb 2009 10:55:18 GMT

to replace disks from mirrored copy, try the command

# pvchange -a y /dev/dsk/c3t2d0

Re: Disk replace (no mirror)

Jeeshan — Tue, 17 Feb 2009 10:59:05 GMT

sorry,

#pvchange -a n <>

Re: Disk replace (no mirror)

Md. Farhan A Azam — Tue, 17 Feb 2009 11:08:57 GMT

Which version of HP-UX is in server, and is this a boot disk with mirror or not mirror.

Re: Disk replace (no mirror)

Ganesan R — Tue, 17 Feb 2009 11:29:58 GMT

Hi,

If the disk is not mirrored, you will lose the data. If OS files are there in the failed disk, need to recover from ignite backup. You may need to restore from backup once you replace the disk for non-os filesystems.

Refer this link on replacing the disk.

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

Re: Disk replace (no mirror)

Anton Yatsun — Tue, 17 Feb 2009 11:55:33 GMT

Hi

System (HP-UX B.11.23 U ia64) have only two disks, put together into vg00. No mirror.
May dd helps or some other possibilities present?

Re: Disk replace (no mirror)

Pete Randall — Tue, 17 Feb 2009 12:09:19 GMT

You are going to need to do an Ignite make_tape_recovery in order to get a bootable back-up tape that can be used to rebuild your vg00 after the disk is replaced. If you do not have a local tape drive then you need to do a make_net_recovery to another server. Since your root VG is compromised, there really is no other way to remove and replace the disk while keeping the system up and running.

http://www.docs.hp.com/en/IUX/

Pete

Re: Disk replace (no mirror)

Ganesan R — Tue, 17 Feb 2009 12:13:55 GMT

Hi,

Have you taken ignite backup of VG00? Does VG00 has only os related filesystem?

It is not preferred to have unmirrored vg00

Re: Disk replace (no mirror)

Anton Yatsun — Tue, 17 Feb 2009 12:22:04 GMT

System now os up and running, so I can take backup at any moment. vg00 have about 10 filesystmes, not only OS.

All filesystems in total use more then 50% of disk space, so I can't add 3rd disk as mirror of vg00.

Yes, I know about mirroring. But the system was setup a years ago by another person.

Re: Disk replace (no mirror)

Ganesan R — Tue, 17 Feb 2009 12:41:27 GMT

Hi,

ok. Few options you can try.

1. Take full ignite backup of vg00.

2. Take the filesystem backup using tar which is there on failed disk

3. If you have free disks/LUNs try mirror both disks with new disks. After successful mirror replace the disk and remirror it.

Re: Disk replace (no mirror)

Bill Hassell — Tue, 17 Feb 2009 13:59:04 GMT

Because the errors are on one of the two disks in vg00 and you have no mirroring, you need to immediately make two Ignite/UX copies for vg00. The bad disk could fail at any time and you will have nothing. A failure of any disk in vg00 (with no mirrors) means the system may no longer boot up (even if it is running now.

Once you have good Ignite backups, replace the bad disk and use the Ignite tape to reinstall vg00 onto both disks. Depending on how important this machine is, you may want to quickly invest in the Mirror/UX product and get two additional disks.

Re: Disk replace (no mirror)

Anton Yatsun — Tue, 17 Feb 2009 14:02:58 GMT

thanks.
I'm planning to take backup and restore it to new disks.

Re: Disk replace (no mirror)

OldSchool — Tue, 17 Feb 2009 14:06:04 GMT

As Bill noted, you may want to add disks and start mirroring as soon as practical.

Additionally, you should consider moving those "10 other filesystems" out of vg00 to new volume groups and reserve vg00 for the OS only.