MC/SG Test Plan

[Juan Luis Morcillo]

Hi!

I have just configured a bizarre cluster with two K360 servers attached to an AutoRAID 12H (2 SCSI controllers per node, primary and alternate path correctly stablished from both nodes).
Everything is working fine.
I am thinking on the way of testing SCSI failover capability... what should I expect if disconecting SCSI cable from the controller on the node with the MG/SG package? Should the machine "panic" (commuting package to the other node), or switch to alternate path on the same node?

[A. Clay Stephenson]

This will not cause a package switch to the other node but just a failover to the secondary SCSI path with the package running on the same node.

[Juan Luis Morcillo]

Great...
That was what I was hoping, but everytime I unplug the primary controller, the primary node crashes!
Should I think on patches or problems with the SCSI cards and cables?
Thank you in advance!

[A. Clay Stephenson]

I would make sure that you kave all the SCSI/LVM patches installed. I am assuming that no other critical devices are attached to these two busses.

[melvyn burnard]

I have to ask whether you have the self-terminating cables in use.
If not, disconnecting a F&W SCSI interface migh t induce a systempanic.
What is the panic string when it fails?
Check /etc/shutdownlog if you are unsure.

[Sanjay_6 · Accepted solution]

Hi Juan,

If you disconnect the SCSI cables from the system without shutting down the system, it will panic the server. To avoid this, you should be using self terminating cables on the server side, this will allow you to disconnect the scsi cable without panicking the system, the connection is like this,

server1 --> self terminating cable --> scsi cable --> disk array --> scsi cable --> self terminating cable --> server2

No you can disconnect the cable coiming from the diskarray to the self termiating cable without panicking the server.

Hope this helps.

Regds

[Luc Bussieres]

Also even if your SCSI cable are terminated correctly the system that has been disconnected from the disc will probably TOC completely since the package will not be able to unmount the filesystem from the disks that have been unplug. Sio the only secure way to failover the package to the other node is to TOC the system that was running it.

luc