[dm-devel] multipath dm setup

[christophe varoqui]

> I have a 3PARdata SAN and I am using 2 qla2300 HBA's connected to a fabric
> switch. There are a total of 2 paths to the SAN per HBA. 
> First off the multipath command never works for me. 
> 
ok,
it seems the getuid function is not the right one for this hardware.
can you track down where it stores the LU WWID ?

you can try hunting for it with the sg_inq command from sg_utils.

example with StorageWorks driven LUNs :
sg_inq -e -o=0x83 /dev/sdb

To code you the right fetching fn, I would need :
o the opcode page
o evpd set or not
o the offset in this page

<snip the nice strace>

> I was able to put a filesystem on the dm-0 device that I created with
> dmsetup without much trouble after I found out the that the multipath table
> arguments changed.
> 
> I didn't see much about LVM2 other than that it uses the libdevmapper
> library.  What I didn't see is how to access the multipath device for an
> LVM2 volume.  Does it automaticly know that it is part of a multipath device
> when I use one of the devices that is a part of the multipath device.

I would recommend blacklisting the paths in the LVM2 config file.
Though, I never tried that : insights from the LVM guys would be
welcome.

regards,
cvaroqui