topic Re: Boot Disk Mirror Failure in Operating System - HP-UX

Boot Disk Mirror Failure

Senthil Kumar V — Mon, 07 Feb 2005 07:13:36 GMT

Hi,

I need clarification on boot disk (with mirror) replacement.

If one of the boot disk fails, should I reduce all LV on the failed disk and also reduce the PV from root VG before I reboot the system for physically replacing disk.

Assume I will be using vgcfgrestore, vgchange and vgsync commands to re-establish the mirror.

Pls revert immediately.

with regards,

Senthil

Re: Boot Disk Mirror Failure

Robert-Jan Goossens_1 — Mon, 07 Feb 2005 07:22:32 GMT

Hi Sethil,

Check this doc.

http://www.unixadm.net/howto/bad_disk.html

Regards,
Robert-Jan

Re: Boot Disk Mirror Failure

Vineesh — Mon, 07 Feb 2005 09:38:59 GMT

hi,

No,there is no need of reducing the lv's and vg's from that failed pv.
pls try the following steps,

shutdown the server and replace the failed harddisk.Boot through alternative path.

#vgcfgrestore -n /dev/vgXX /dev/rdsk/cXtYdZ
#vgchange -a y /dev/vgXX
#mkboot /dev/rdsk/cXtYdZ
#mkboot -a "hpux(;0)/stand/vmunix" /dev/rdsk/cXtYdZ
#lvlnboot -R
#vgsync /dev/vg00

regds,

Re: Boot Disk Mirror Failure

Geoff Wild — Mon, 07 Feb 2005 09:59:53 GMT

That depends...

1) If the disk is completely "dead", such as if you run ioscan and status is "no_hw" then you can hot swap the disk online.

2) However in circumstances where the disk has not fully failed please do one of the following to avoid data corruption :

a) reduce mirror before replacing the disk
b) deactivate VG before replacing the disk
c) shutdown system to replace the disk

Rgds...Geoff

Re: Boot Disk Mirror Failure

B. Hulst — Mon, 07 Feb 2005 10:52:15 GMT

Hi,

With systems that have hotswappable disks you don't halt the server and replace the corrupt bootdisk mirror.

The trick was just to have the mirror so you don't need to reboot!

I normally do this:

#vgcfgrestore -v /dev/vg00 (you must have of course a copy made with vgcfgbackup ever...)
#mkboot -l (list what do we have?)
#mkboot -a "hpux(;0)/stand/vmunix" (put bootfile)
#vgchange -a y /dev/vg00 (make available)
#vgsync /dev/vg00
#lvlnboot -R (resync all boot info)

And check at startup if dump,swap are okay after a reboot with command 'dmesg'.

Basically you don't shutdown any application or server for this replacement operation. :-)

Regards,
Bob

Re: Boot Disk Mirror Failure

bhavin asokan — Tue, 08 Feb 2005 01:31:13 GMT

hi,

see the attached document.it gives somany ways to replace a faulty disk depends up on it is mirrored ,hotswappable,etc.

regds,

Re: Boot Disk Mirror Failure

bhavin asokan — Tue, 08 Feb 2005 01:32:01 GMT

hi ,
sorry forgot to attach file

regds,

Re: Boot Disk Mirror Failure

Senthil Kumar V — Tue, 08 Feb 2005 02:44:48 GMT

Dear All,

I know the ways of replacing a failed root disk with mirror. But my question is very simple. Is it essential to reduce lv and pv from root VG before rebooting the server for physical replacement of disk?

regards,

Senthil

Re: Boot Disk Mirror Failure

B. Hulst — Tue, 08 Feb 2005 02:54:59 GMT

Hi,

No need to reduce anything if you have hot swap disk.

Just take the hot swap disk out, run the command I gave earlier after you inserted the new empty disk.

However with non-hot-swap-so-screwed-in-disks you can reduce the lv from the failed disks.
then halt and replace the disk and remirror bootdisk once you reboot.

This way you can always boot, from the remaining disk.

Also if you want to boot with the broken mirror bootdisk you can boot also with hpux -lq

Regards,
Bob

Re: Boot Disk Mirror Failure

Robert-Jan Goossens_1 — Tue, 08 Feb 2005 03:56:28 GMT

The latest models n-class l-class and newer all have hot-swap internal disks. For these systems you do NOT need to lvreduce before you can replace a failed disk.

replace a failed disk
--
Assume I will be using vgcfgrestore, vgchange and vgsync commands to re-establish the mirror
--
Yes correct.

Re: Boot Disk Mirror Failure

Senthil Kumar V — Tue, 08 Feb 2005 06:09:06 GMT

Dear All,

Thanks for the clarification.

regards,

Senthil

Re: Boot Disk Mirror Failure

Senthil Kumar V — Tue, 08 Feb 2005 06:11:15 GMT

Thanks to all for clarification.