Hello!
I have servers ESXi 5.5 and vCenter 5.5.
I need to temporarily disconnect the storage (disk array) from the SAN switches, reconfigure the SAN switches (add a new SAN switches to the stack) and then reconnect the storage (disk array) through the new SAN switches.
I have executed "Unmount datastore" from vSphere Client for this datastore.
Should I perform from vSphere Client operation Configuration\Devices -> "Detach" on each ESXi host before detaching the storage (disk array) from the SAN switches?
If "Yes", then how to mount the datastore again after connecting it to the SAN switches?
IF there is two, you should be able to bring down the one make updates, do a rescan so esxi sees the new patch, and do the same for the other one. To do what your specifically asking if the all the information is the same the unmount is fine, and just remount them after your done, but you may need to rescan before you bring the back up as well.
This means that if the datastore has several paths to the ESXi server, then you can simply disconnect the disk storage first from one SAN switch, then after configuring the first port, disable the second port and also configure. And you don't need to do Detach for these servers.
But if the server has only one FC port and one path to that datastore. Do you need to perform "Detach" for him?
Detaching is only really needed it your getting rid of the device permanently. I would also upgrade 5.5 is pretty old at this point, and I'd look at getting a second switch if the servers running here are important.