topic Re: General query on root disk mirroring.... in Operating System - HP-UX

General query on root disk mirroring....

jimbe21688207 — Mon, 21 Mar 2011 10:02:32 GMT

Dear All,

A query on root disk mirroring in any version 11iv1/v2/v3.

If my primary disk goes down due to any reason, is server reboot/hung or it keep working from the secondary disk?..

Regards
Jimbe....

Re: General query on root disk mirroring....

Bill Hassell — Mon, 21 Mar 2011 11:25:46 GMT

Assuming that you correctly followed all of the steps for mirroring your root disk, a disk failure will allow the system to keep running. However, if the two disks are on the same controller, an electronic failure in a disk may lockup everything on that bus. That's why mirroring should be done with disks on different controllers. If you reboot (and you've setup the two disks correctly, a failed disk will cause the system to boot from the alternate disk.

Re: General query on root disk mirroring....

Torsten. — Mon, 21 Mar 2011 12:12:58 GMT

If all the LVOLs are mirrored (including swap!), the system continues to run.

But in case of a reboot you need to boot in quorum mode because of the missing disk.

Re: General query on root disk mirroring....

Emil Velez — Mon, 21 Mar 2011 13:03:49 GMT

need to make sure the auto file on your system says

boot vmunix -lq

hpux -lq

depending on whether it is PA or IA.

if you boot vg00 without quorum your system should keep on running as long as all of the LVs are still available from one of the mirrors.

IF the disk comes back it should sync up automatically.

it should be the same if you use VxVM for your boot disk. BASE VxVM allows you to mirror the boot disk free.

Re: General query on root disk mirroring....

Jose Mosquera — Mon, 21 Mar 2011 15:27:02 GMT

Hi,

Please ensure that autoboot/autosearch capabilities are ON/enabled status.
#setboot
Primary bootpath : 8/4.5.0
Alternate bootpath : 8/16/5.0.0

Autoboot is ON (disabled)
Autosearch is ON (disabled)

To enable autoboot:
#setboot -b on
To enable autosearch:
#setboot -s on
#setboot
Primary bootpath : 8/4.5.0
Alternate bootpath : 8/16/5.0.0

Autoboot is ON (enabled)
Autosearch is ON (enabled)

Also ensure that secondary system loader (SSL) utility load "hpux -lq" (man hpux) to boot the system with quorum override option. This option is used in a scenario where a disk is removed from the system or is otherwise unavailable, but the corresponding entry for the physical volume has not yet been removed from the volume group using vgreduce.
#mkboot -a "hpux -lq" /dev/rdsk/c[n]t[n]d[n]

-a option creates an autoexecute file AUTO on device, if none exists. mkboot deposits auto_file_string in that file. If this string contains spaces, it must be quoted so that it is a single parameter.
#man mkboot

Please keep in mind that "-lq" flag is supported by LVM layouts only.

Rgds.

Re: General query on root disk mirroring....

P Arumugavel — Mon, 21 Mar 2011 16:29:32 GMT

Hi,

It should keep working if your mirroring is proper. Then what is the use of mirroring if goes to reboot.

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00872150&cc=us&dlc=en&lc=en&jumpid=reg_R1002_USEN

Rgds...

Re: General query on root disk mirroring....

jimbe21688207 — Tue, 22 Mar 2011 04:32:02 GMT

Thank u All, closing the thread....