abnormal MPIO delay and explorer delay toleration.

Hi,

We have a win2008r2 server with MPIO installed. The host has two iSCSI path to a dual-controller SAN storage. We are trying to test the LUN trespass latency by doing a explorer copy operation.

Testing procedure is as below:

1. Begin the copy on a SAN LUN owned on controller_A
2. In the middle of the copy, we pull out the NIC cable to simulate an link down situation.
3. Explorer began to continue to copy after more than 2mins, which is really wired.
4. We can see a SCSI Mode Select Page 2C was received on the controller, which meas the MPIO driver did send a request to ask for LUN trespass to controller_B.

Now, we want to know two things:

(1) Why did it took more than 2mins to make the MPIO driver to send out a SCSI LUN trespass command? Is it tunable?

(2) Why explorer can tolerate more than 2mins i/o delay still being alive? It shouldn't be that long, there must be something happened.

Could anyone show your ideas on this issue?

thanks a lot!

Ah_Chao|| MCSE,VCP,EMCSAe