RE: [dm-devel] Unable to use multipath with LVM2

["Magni Fabrizio" <Fabrizio Magni rasnet it>]

Hi Lars,

> It'd be helpful if you actually reported which distribution you're
> talking about ;-)
> 

luckily you know my situation.

> But looking at your version, I guess you might be running SLES9. In
> which case SP2 should help address your troubles:
> http://portal.suse.com/sdb/en/2005/04/sles_multipathing.html
> 
> Please try and get access to the beta via your support contact.
> 

I'm going to try soon.

> > If I insert aliases in multipath.conf and modify udev.rules 
> I can see
> > symbolick links wichi can be used in failover or multibus 
> (tested) but
> > they are not seen by the LVM2 (even modifying the filter in 
> lvm.conf and
> > specifying "types").
> 
> With those changes LVM2 is supposed to recognize them. Not sure why it
> doesn't for you.
> 
> > What devices should the LVM scan to use multipathed PVs?
> 
> Either the /dev/disk/by-*/ files, or /dev/dm-*; either will do. It's
> just important that it only uses those paths and doesn't use the raw
> disks (/dev/sdX).
> 

/dev/disk/by-*/ can be scanned but they don't work properly on top of
multipath since they are linked directly to the "basic devices"
/dev/sd*.

I really don't understand why /dev/dm-* cannot be scanned properly by
the LVM2...

Fabrizio