I had a quick question about the FI's ability for multipathing.
As in the pic I've attached. If the the FC switch with the big circle around it, and line through it goes down. What will happen to the VM's on my ESXi hosts do? How will this failover, will there be some sort of multipathing for storage initiated on the FI's that will reattach the LUN's through FI - A?
The operating system must be "multipath aware"
Multipath may be load balance or failover, anyway, the SO monitor all the paths and change when one of them goes down. This is done without packet loss in a few seconds.
From the storage perspective, it may forward the traffic to the owner controller of the LUN or move the LUN to the controller with inbound traffic.
Hope this help.
I don't use ESX, but, in a normal implementation, ESX do all the work. VM's are unaware about FC stuff, they only see an internal HD.
I guest you can virtualize HBA and present it to the VM's, but this is a more complicated aproach and shuld be considered only if you need hi security inside your SAN.