DL380 and MSA device names

[Timo J]

Configuration:

- DL380 packaged cluster with MSA500
- Mirrored os disk pair on both disks
- mirrored data disk pair on common storage (MSA500)

Recently I added one disk to first node and took OS backup to it (Mondoarchive). Then I switched both OS disks to new ones and restored the OS from that one extra disk.

Restore went ok, node joined ok back to new cluster and so on. Only thing that failed, is the cluster lock lun device name (and also the clustered disk device name).

Included is present (faulty) fdisk output. As you can see, there's disk device named /dev/cciss/c0d2. But the initial name of that disk was /dev/cciss/c0d1. And also the other cluster node sees that device as /dev/cciss/c0d1. Because of that, cmlocklund reports following warning to syslog:

Jan 30 11:15:05 a cmlocklund[3345]: Could not open cluster lock LUN /dev/cciss/c0d1p1: No such device or address
Jan 30 11:15:05 a cmlocklund[3345]: Until it is fixed, a single failure could
Jan 30 11:15:05 a cmlocklund[3345]: cause all nodes in the cluster to crash.


So the question is that how do I change that device name back to /dev/cciss/c0d1? I've removed the extra
disk and rebooted the system already but still fdisk sees the device as /dev/cciss/c0d2.

[John Bigg]

Unfortunately, this is not possible. The cciss devices write the lun id on the raw disk so the disks can be plugged in anywhere and the cciss driver knows what the lun is. You may remember being asked for or specifying the lun number when you created the new lun.

What you can do instead though is to change the cluster lock LUN configured in Serviceguard. Edit the cluster ascii file and change the device name specified, halt the cluster and run cmapplyconf to re-build the configuration and then you should be all set to re-start the cluster using the new device.

[Timo J]

That's weird, because as you might notice from my initial posting, the device name somehow changed from c0d1 to c0d2 while I was switching and adding disks...

Yep, I could change the configuration so that lock lun device name is c0d2p1 on first node and c0d1p1 on second node. But in addition to that, I also have that shared VG for both nodes on MSA. And that VG also shows different on first and second node.

So additional question would be that where the OS stores that old information about device names and how to refresh that information?

And because that shared volume shows different device names to different nodes, I doubt that the lun ID is not located on raw disk.

[Timo J]

OK, solution found. That extra disk I mentioned, was still visible when checking with Array Configuration Utility (of course the status of that disk was failed). Just deleted it and rebooted the system and the device name was again /dev/cciss/c0d1.