topic Re: Turn off LVM autoswitch (pvchange -S n) in Operating System - HP-UX

Turn off LVM autoswitch (pvchange -S n)

Daniel Neeves — Wed, 24 Oct 2007 10:49:51 GMT

Question is, does running this command on a disk device file update the LVM structure on the physical disk and thus it will be persistent across a reboot or is it like the -s (lowercase s) which will only survive until VG is restarted on server is rebooted ?

Also, we run S/G here so I'm assuming if the command pvchange -S (uppercase S) is run it only needs to be run on one node in the cluster.

Thanks
Dan

Re: Turn off LVM autoswitch (pvchange -S n)

whiteknight — Wed, 24 Oct 2007 22:28:51 GMT

Dan,

What LVM cumulative patch you are installing ?

The pvchange command provides several options for managing LVM
behavior with paths:
â ¢ The -s (lower case s) option (immediate switch) requests that the
specified path be used for all future I/O.

â ¢ The -S (upper case s) option (autoswitchback) when set (default
value), tells LVM to automatically switch to the best available path. When
autoswitchback is disabled, LVM will still switch paths when the current path
becomes unavailable, but it will not switch back to a higher priority path
that returns. The pvdisplay command will show the current autoswitchback
setting.

WK

Re: Turn off LVM autoswitch (pvchange -S n)

Daniel Neeves — Thu, 25 Oct 2007 04:15:06 GMT

If you meant what LVM patch do we have installed its PHKL_34518. I know what the switches to pvchange do, I wanted to know if issuing a pvchange -S disk/device would remain after reboot and would it also remain after failover to alternative node in S/G cluster.

Re: Turn off LVM autoswitch (pvchange -S n)

Denver Osborn — Thu, 25 Oct 2007 21:19:33 GMT

It's similar to setting the pv timeout (-t). Yes, changes to the autoswitch setting will survive a reboot. You can make the change from the active node and you're done.

-denver

Re: Turn off LVM autoswitch (pvchange -S n)

whiteknight — Fri, 26 Oct 2007 01:26:31 GMT

Dan,

Yes, -S it will remain even after you reboot.

WK

Re: Turn off LVM autoswitch (pvchange -S n)

Daniel Neeves — Fri, 26 Oct 2007 04:11:18 GMT

Thanks guys. Managed to test it yesterday to confirm your answers.