topic Re: switching primary disk with mirrored disk in Operating System - HP-UX

switching primary disk with mirrored disk

ROSS HANSON — Fri, 12 Jun 2009 13:07:03 GMT

Hello,

I have a rx2620 with two drives, primary and mirrored. Can I shut down the system, reverse the drives physically, and then still boot up to the mirrored drive which now is at the primary drive's hardware path?

I have mirrored the disk already and have shutdown and rebooted the box to the alternate drive without a problem so I know that that the mirroring portion works.

Re: switching primary disk with mirrored disk

Mel Burslan — Fri, 12 Jun 2009 13:08:59 GMT

If both drives are identical, I do not see any reason why this should not work but still can not grasp the need for such and exercise, especially after you have verified alternate boot path is working fine.

Re: switching primary disk with mirrored disk

Steven E. Protter — Fri, 12 Jun 2009 13:11:12 GMT

Shalom,

You can do this.

Doing so has no practical effect.

To test mirror configuration, you need to pull out the primary and boot off the secondary.

SEP

Re: switching primary disk with mirrored disk

Sunny123_1 — Fri, 12 Jun 2009 13:11:22 GMT

Hi

If you checked your disk then you can go ahead for this activity.

Regards
Sunny

Re: switching primary disk with mirrored disk

ROSS HANSON — Fri, 12 Jun 2009 14:22:06 GMT

Well,
For the purpose of testing... I did this.

I shutdown the rx2620, reverse the physical location of the primary and mirrored drives, then booted up the rx2620.

Once, during the boot process, when the system got to the EFI I did nothing because as far as the box knew it was booting from the primary disk. This was not the case though. The box would not boot up nor would it boot up when, in the efi, I chose to boot up to the alternate disk which now has the primary boot drive in it.

I was wondering if anyone knew of any EFI settings, that would force the booting of the mirrored disk in the primary disk's location?

Re: switching primary disk with mirrored disk

OldSchool — Fri, 12 Jun 2009 14:39:28 GMT

the purpose of mirroring is so you don't have to physically switch the disks like that.

as noted, you want the system to be able to detect the failed primary and switch to the alternate....which your test doesn't appear to prove.

pull the primary and see if it will automatically boot from the alternate.

note that on pa-risc systems and 2 drives you had to use the "-lq" option to allow it to boot w/o quorum when there was a failed disk...not sure if that applies here or not tho...

Re: switching primary disk with mirrored disk

Michal Kapalka (mikap) — Fri, 12 Jun 2009 14:51:25 GMT

hi,

if you switch the disks,

i think you need to add a new boot option in the efi boot menu.

mikap

Re: switching primary disk with mirrored disk

ROSS HANSON — Fri, 12 Jun 2009 15:02:44 GMT

Actually,
I did pull the primary harddrive out while the system was up and running and yes the system did stay up and ran just fine.

What EFI additions would I have to make to boot to the mirrored disk if it was in the primary boot disk's spot??

Re: switching primary disk with mirrored disk

sujit kumar singh — Fri, 12 Jun 2009 15:18:59 GMT

Hi

as you are interchanging the disk i would like to know what exactly was the EFI error message that you got.

anytime if the Physical path of a disk changes, in General LVM scnarios as till 11.23, the LVM Configuration needs to be updated for that(those) disks which is bascially using the vgexport/vgimport of the VGs.

make sure that for both the PVs you are having

#echo "boot vmunix -lq" > /tmp/AUTO
#efi_cp -d /dev/rdsk/boot_disk1_p1 /tmp/AUTO /EFI/HPUX/AUTO
#efi_cp -d /dev/rdsk/boot_disk2_p1 /tmp/AUTO /EFI/HPUX/AUTO

Well if interchanged the disks, boot usinng one of the paths selecting from the EFI , boot in LVMMaintenance mode that is hpux -is and do a vgexport of root VG , mkdir /dev/vg00 and mknod /dev/vg00/group c 64 0x000000 , vgimport /dev/vg00 /dev/dsk/cXtYDZ /dev/CxtYDz,
followed by lvlnboot -v and lvlnboot -R and also check /stand/bootconf.

#setboot -p -h -a -b on

""Shall be helpful if you could share the EFI failure messages as you might have occured while booting after interchanging the disks.""

but if you are using 11iv3 Sep 2008 release or further that has the feature of self-boot-healing that rescans all disks at boot time and imports the root VG disks and boot -- Well that is mentioned in New GenerationMass Storage Stack .. You can give a test if you have 11iv3 Sep 2008 Post release.

regards
sujit

Re: switching primary disk with mirrored disk

sujit kumar singh — Fri, 12 Jun 2009 15:20:07 GMT

hi
" LVMMaintenance mode that is hpux -is "

should read as

"LVMMaintenance mode that is hpux -lm"

please correct.

regards
sujit