OpenSM Failover

Aaron Knister
2009-10-10T23:38:23Z

I'm not sure if this is the right place to post about this issue, but
here goes-

I'm having problems with OpenSM failover.

I have two nodes running opensmd version "3.2.6_20090317" from RHEL
5.4. I'm using a configuration file on both generated using opensm -c.
When I start the subnet manager on node a, everything is fine. It
appears to reassign itself a lid of 1 which I think is expected. When
I started the subnet manager on node b everything is fine. If you
query its lid it shows the subnet manager in a standby state. Now for
the fun. If I stop opensmd on node a (service opensmd stop) then all
of the traffic on the fabric stops. It takes node b's OpenSM instance
about 30 seconds to realize that node a's subnet manager is dead and
come up in the master state. Now when node a's subnet manager comes
back (service opensmd start), all traffic on the fabric stops and node
b's subnet manager goes into the standby state...but node a's subnet
manager doesn't take over the fabric and come up as master for about
another 40 seconds (during this time the no traffic passes over the
fabric). The below logs should help illustrate what I'm seeing

Oct 10 19:14:14 node-a OpenSM[14132]: Entering DISCOVERING state
Oct 10 19:14:14 node-a OpenSM[14132]: Entering MASTER state
Oct 10 19:14:14 node-a OpenSM[14132]: SUBNET UP

Oct 10 19:14:25 node-b OpenSM[11197]: /var/log/opensm.log log file
opened
Oct 10 19:14:25 node-b OpenSM[11197]: OpenSM 3.2.6_20090317
Oct 10 19:14:25 node-b OpenSM[11197]: Entering DISCOVERING state
Oct 10 19:14:26 node-b OpenSM[11197]: Entering STANDBY state

Oct 10 19:15:44 node-a OpenSM[14132]: Exiting SM
Oct 10 19:16:16 node-b OpenSM[11197]: Entering DISCOVERING state
Oct 10 19:16:16 node-b OpenSM[11197]: Entering MASTER state

Oct 10 19:18:52 node-a OpenSM[14213]: /var/log/opensm.log log file
opened
Oct 10 19:18:52 node-a OpenSM[14213]: OpenSM 3.2.6_20090317
Oct 10 19:18:52 node-a OpenSM[14213]: Entering DISCOVERING state
Oct 10 19:18:53 node-b OpenSM[11197]: Entering STANDBY state
Oct 10 19:18:53 node-a OpenSM[14213]: Entering STANDBY state
Oct 10 19:19:33 node-a OpenSM[14213]: Entering DISCOVERING state
Oct 10 19:19:33 node-a OpenSM[14213]: Entering MASTER state
Oct 10 19:19:33 node-a OpenSM[14213]: SUBNET UP

We have opensm 3.2.5_20081207 (ofed 1.4) on another cluster and it
fails over and fails back almost instantly with seemingly no traffic
interruption if you gracefully stopped the active opensmd instance
(service opensmd stop). Is the behavior I'm seeing considered normal?
I can understand the 30 seconds for the initial failover but why the
40 second failback when the original master comes back? Any help is
appreciated :)

BTW my switch is a Qlogic 12800-180 with the latest firmware and the
HCAs are Mellanox MT26428 running firmware version 2.6.648.

Thanks!

-Aaron