Hi, I had a problem similar to the one described in http://www.redhat.com/archives/dm-devel/2006-July/msg00034.html at a customer site (RHEL/RHCS 4.4) and found out that the solution is actually quite easy. You just have to blacklist the LUNZ's WWID. Since I found no related information anywhere I thought I'd post it here. Our setup: a pair of Sun x4200 servers w/ Emulex LP11000 HBAs, RHEL4.4, CLARiiON CX3-20, EMC / Broadcom FC Switches. So what I did was: - boot up the machine with FC cables pulled - rmmod / modprobe lpfc - this re-scans the bus and creates the necessary kernel devices. You'll see the LUNZ's in /proc/scsi/scsi. - modprobe dm-multipath and run "multipath -v2" with just sda and sdb blacklisted (internal disks) - the command gives you the WWID of the LUNZ (size 1 GB, it's almost certainly mpath0), plus lots of error messages that dm-emc (or was it dm-multipath itself?) has failed paths for one of the devices. - add this WWID to the blacklist in /etc/multipath.conf - you'll have to reset the machine or switch it off hard because kpartx is sitting on /dev/mapper/mpath0 in state "D". RHEL will wait forever and not shut down if you only do a "halt". - next time the box comes up, everything is fine. - I usually give all other WWIDs aliases in a multipaths{} section in order to have a consistent naming scheme, and use the alias names in /etc/fstab or wherever. Very handy in a HA/failover setup. Strange thing is, and this is almost certainly related to the CLARiiON CX3-20 setup, on a second pair of machines attached to the same CX box, we have no LUNZ whatsoever. Any insight why and when this is so? The point is, you usually don't want the LUNZ devices if you want to do multipathing. -- Harris's Lament: All the good ones are taken. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
