Question:

In which condition / situation the Trespass occurs where multi path configuration with 2 passes per SP? Because it took much time to happened Trespass after I removed the both cables for SP A. By which threshold will the Trespass occur?

And how about Trespass back? This also took much time.

Answer:

Once the IO count delta between non-optimized and optimized path exceeds 140K, the LUN is trespassed (/ trespassed back).

There is also the following on page 14 of “EMC UNITY: HIGH AVAILABILITY A Detailed Review”.

“This operation is completely transparent to the host and removes the need to trespass the resource to complete the I/O. However, if a large number of I/Osare received down the nonoptimized path, the Unity system trespasses the LUN to the peer SP in order to optimize the data path.”

Author: Hiroki Kobayashi