Monday, June 27, 2011

multipathd woes!

Today, playing with multipathd - it's not often I have a server, FC switches AND the storage at the same time to lay my beer-tainted hands on - I ran into an issue: no matter what, multipathd wouldn't hear a thing about my LUNs.

Tried a lot, installing some scsi debugging packages - which showed me that the storage was indeed presenting the LUNs, modprobing some modules and things.

Until I ran "udevinfo -e", which exports all the devices the kernel sees. Which also told me that the WWID have to be lower case!

I had done a couple of copy-paste between the SAN configuration screen and my /etc/multipathd.conf: the SAN configuration page gives me the WWID with capital letters (ex 35001ADE...), where udev reports lower case letters (35001ade...).

A quick trip to /etc/multipath.conf, change all the letters to lower case and ... voila! Both multipathd and I are happy.