On Thu, Dec 22, 2005 at 09:22:10PM -0600, Jeffry R. Abramson wrote:
> On Tue, 20 Dec 2005 17:57:30 +0000, John Hearns
> <[log in to unmask]> wrote:
> 
> >
> >I've set up LinuxHA and high availability NFS, and would prefer to use a
> >dual-port SCSI array for this, or a SAN setup.
> >Remember to mirror the lock files between the two systems also.
> >
> >I've used DRBD, but would advise monitoring if it is working, ie. if it
> >fails on the recipinet machine the mirror will be out of sync and you
> >need to restart it.
> 
> Speaking of SAN's, has anyone gotten the multipath feature in SL42 to work?
>  We have an IBM blade equipped with a dual-port Qlogic controller connected
> through two independent fabrics to a DS400/Adaptec array with a dual-port
> controller.  fdisk -l shows two paths to every logical array, ie. each disk
> shows up twice.

You should be seeing more than that, you have at least four paths
(2xHBA ports x 2xcontroller ports).

> The instructions make it look easy (comment everything out
> from /etc/multipath.conf, start up multipathd and away you go). Running
> multipath -v2 -l shows nothing.  multipath -v3 shows that it sees all of the
> devices but I don't know how to decipher where it is going wrong (I'd attach
> the output but I'm typing this from home).  Ideas? -- Jeff

Use multipath -F and try again.

Other than that check with scsi_id that the paths are to the same
device, e.g.

# for x in sdb sdc sdd sde; do /sbin/scsi_id -g -u -s /block/$x; done
3600508b4000106f30006300000240000
3600508b4000106f30006300000240000
3600508b4000106f30006300000240000
3600508b4000106f30006300000240000

That's what multipath does, too, to construct the multipath maps.
-- 
Axel.Thimm at ATrpms.net