topic Re: Bad disk in lvmtab in Operating System - HP-UX

Bad disk in lvmtab

joe_91 — Thu, 27 Apr 2006 14:24:05 GMT

we have a baddisk(alternate) in lvmtab.the ce is coming to replace the bad disk. i have to get the disk replaced, and mirror the os.

tell me which option is good.

A.
once the disk is replaced..

go to hpux -lm
vgcfgrestore -n /dev/vg00 /dev/rdsk/c6t0d0
vgchange -a y vg00
shutdown -r -y 0
once in multiuser mode
vgextend and continue to mirror

B.

Before replacing the disk..
take to hpux -lm mode
vgexport -m /dev/vg00
mkdir, mknod and vgimport <> good disk
Then shutdown and replace the disk and take to multiuser mode and mirror.

Question:
1.which option is better A or B?

2.Also can i have apps/DB's up while i do the mirror. The client is looking at minimum downtime and questions "If sun can do the mirror while apps are UP why not HP"?

This machine runs 11.11

Thanks in advance

Joe

Re: Bad disk in lvmtab

James R. Ferguson — Thu, 27 Apr 2006 14:31:15 GMT

Hi Joe:

I suggest that you review the various scenarios here:

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

Yes, you can recreate mirrors while users are using your applications. They may experience some performance degradation, but there is no problem doing this, otherwise.

Since you mention vg00 replacement and then speak of applications and databases, I have to point out that I hope your vg00 is a pristine implementation of only the operating system and not a mixture of operating system logical volumes *and* applications/database. If it is, you make upgrades and potential recovery much more difficult.

Regards!

...JRF...

Re: Bad disk in lvmtab

Florian Heigl (new acc) — Fri, 28 Apr 2006 00:41:14 GMT

Usually (that is about 199 out of 200 disk failures) You'll be able to recreate the mirrors online.

Stick to the proposed pdf and You'll be fine; ask us when any questions come up.

Re: Bad disk in lvmtab

Raj D. — Fri, 28 Apr 2006 01:16:32 GMT

Hi Joe ,

You can do it online .
If the disk it hotswap , let the CE to swap it online.

Then you can floow this steps:

1. Check in ioscan if it shows CLAIMED.
# ioscan -fnC disk

2. ok , proceed to remirror the disk.
# vgdisplay -v /dev/vg00
(If the 2nd disk shows as unavailable)

move lvmtab and pvcreate it .
# mv /etc/lvmtab /etc/lvmtab.ok
# pvcreate -B /dev/rdsk/c?t?d?

move the lvmtab back
# mv /etc/lvmtab.ok /etc/lvmtab

3. # vgcfgrestore -n /dev/vg00 /dev/rdsk/c?t?d?

4. # vgchange -a y /dev/vg00

5. # mkboot /dev/rdsk/c?t?d?
# mkboot -a "hpux -lq" /dev/rdsk/c?t?d?

6. vgsync vg00

Resyncronizing ....
wait till it completes.

7. Check with :
# lvlnboot -v and pvdisplay , vgdisplay.

Cheers,
Raj.

Re: Bad disk in lvmtab

Raj D. — Fri, 28 Apr 2006 01:19:22 GMT

Joe,

Also check out the document : RootDiskMirrir.pdf .

Cheers,
Raj.

Re: Bad disk in lvmtab

joe_91 — Fri, 28 Apr 2006 12:51:09 GMT

So these steps can be done in multiuser mode if hot swappable right?

Joe

Re: Bad disk in lvmtab

James George_1 — Fri, 28 Apr 2006 13:10:16 GMT

Hi Jo

Yes, Everything can be done on online , in this case ...

# ioscan -fnC disk
# pvcreate -fB /dev/rdsk/cxtxd0
# mkboot -l /dev/rdsk/cxtxd0
# mkboot -a "hpux -lq (;0)/stand/vmunix" /dev/rdsk/cxtxd0
# lifcp /dev/rdsk/cxtxd0:AUTO -
# vgextend /dev/vg00 /dev/dsk/cxtxd0
bdf
for i in 1 2 3 4 5 6 7 8 ;do
lvextend -m 1 /dev/vg00/lvol$i /dev/dsk/cxtxd0
done

#lvlnboot â R

Re: Bad disk in lvmtab

Torsten. — Fri, 28 Apr 2006 13:58:39 GMT

We have to talk about where your disks are.

Just in case this is an old K-Class and you talk about internal disks, which are not hot-swappable.