05-17-2017 12:43 PM - edited 05-17-2017 12:45 PM
Hi, I have a scenario where I could use a peer review.
We have three FC switches in our environment, they are ISL'd as shown below.
Switch 1 <-> ISL <-> Switch 2 <-> ISL <-> Switch 3.
The plan is to retire switch 2, however its ISL link to switch 3 is still required because there are hosts attached to Switch 1 which need to access a storage array connected to switch 3.
With all three switches in its current state, is it possible to establish an ISL between Switch 1 and Switch 3? All switches have the same zoning configuration. I have a escalation support case opened, however I was also hoping to leverage some of the other SAN Admin's experience out there to see if anyone has come across this scenario.
05-17-2017 11:18 PM
yes, you just need to add ISLs between switch 1 and switch 3. Triangular design is pretty common.
Once you enable the first ISL between switch 1 and switch 3 all the traffic between devices on these two domains will be all rerouted to the new ISL(s) only due to lower link cost / hop count / FSPF (Fabric Shortest Path First).