topic Re: Altenate path for boot disk in Operating System - HP-UX

Altenate path for boot disk

Madhus — Tue, 06 Feb 2007 10:01:24 GMT

I am running HP-UX 11.11 and my boot disk is from SAN and it is configured with two independet paths (through different fabrics). Whenever primary path goes off, instead of switching boot disk to the secondary path, server crashes. Any idea why it is happening so. Please note that both of the paths are working fine because half of the other disks use first path as primary path and rest uses seond path as primary path. Is it something alternate path not supported for root disk?

Re: Altenate path for boot disk

A. Clay Stephenson — Tue, 06 Feb 2007 10:11:25 GMT

Because you are confusing the role of an alternate boot path with that of an LVM alternate pv-link or pv-path. The alternate boot path is intened to be used as a path to a completely separate, bootable disk or LUN --- which might mirror every LVOL in the primary boot device. If you configure alternate pv-links using change then the failover will autommatically occur when the primary pv-link is unavailable.

Re: Altenate path for boot disk

A. Clay Stephenson — Tue, 06 Feb 2007 10:12:52 GMT

Ooops, this phrase:
If you configure alternate pv-links using change
should be:
If you configure alternate pv-links using pvchange

Re: Altenate path for boot disk

Torsten. — Tue, 06 Feb 2007 10:18:41 GMT

Welcome to the forums!

As mentioned above, there is a difference between alternate boot path and alternate links from the LVM point of view (pvlinks).

You should check

vgdisplay -v vg00
lvlnboot -v
setboot

first.
The vgdisplay output should be similar to this (2 mirrored disks with alternate links in a SAN):

...
--- Physical volumes ---
PV Name /dev/dsk/c2t0d1s2
PV Name /dev/dsk/c14t0d1s2 Alternate Link
PV Name /dev/dsk/c4t0d1s2 Alternate Link
PV Name /dev/dsk/c10t0d1s2 Alternate Link
PV Status available
Total PE 3000
Free PE 0
Autoswitch On

PV Name /dev/dsk/c12t0d1s2
PV Name /dev/dsk/c8t0d1s2 Alternate Link
PV Name /dev/dsk/c18t0d1s2 Alternate Link
PV Name /dev/dsk/c6t0d1s2 Alternate Link
PV Status available
Total PE 3000
Free PE 0
Autoswitch On