Is moving all active ports to another VSAN disruptive?..

[Artem Troitsky]

Hi! I moved all active ports to another VSAN and this caused a server to failure. I know that this can be because of the small time-out values at the operating system or bad multipathing, but how large a time-out can be in a such reconfiguration?.. What if the server can't survive any storage loss and we move server and storage array ports to another VSAN? I wonder if it can be done without any traffic interruption...

[Vincent Jamart · Accepted solution]

Hi Artem,

Changing server from VSAN is a disruptive process for each path you're acting on: that means if you're not having dual fabrics and proper multipathing configuration, the server will lose access to its LUN for a certain amount of time. Depending on the operating system you might expect various behaviors (kernel panic, SCSI errors, CPU in I/O wait until timeouts,...). Consider it even more restrictive when booting on SAN or when swap memory is also on a SAN LUN.

It's always good practice to work one one fabric at a time by disabling the path attached to it from the OS perspective (if multipath software is not set in a failover mode).

Changing VSAN membership for a FC port on the MDS9000 means that the initiator HBA has to log (FLOGI) into a new VSAN where the DomainID is different from previous VSAN, so its FCID will change also. It is same effect as moving fibers to another physical SAN from the host perspective.

[Artem Troitsky]

Thanks for the answer! I will check multipathing better next time...