I have a single Brocade Silkworm 200e switch in production right now. The corp exchange server and 3 ESX 3.5 hosts are connected to the clariion cx3 array through it. Port 0,1 are SPA0 and 1, and port 4,5 are SPB0 and 1.
My plan is to add a Brocade Silkworm 300 switch next to the 200 (it's already racked and powered on), go to the datacenter and pull SPA1 and SPB0 out of the 200 and insert them into ports in the 300 switch.
I'm a little paranoid of pulling out FC paths that are in production. I have a logical assumption that things will just fail over to SPA0 and SPB1 and A1 and B0 won't be missed. However, I'd like to have 100% firm understanding of what I could do to further minimize risks if possible.
If a LUN is currently owned by SPA, does it automatically utilize both SPA0 and SPA1 in round robin or does the switch prefer a particular path exclusively unless failed off of it? Example - is exchange server using SPA0 or SPA1, or does it use both 0 and 1 active/active?
I'm guessing that if it's using both paths to a SP active/active that disrupting one of them is less risk because I'm assured it is using the other path already without trouble. I'm scared of forcing failover to an alternate path it hasn't used before and then finding out that cable was wonky or something.
Should I be totally disruptive to the company and shut down all virtual machines and the exchange server just to be sure no data corruption happens in the event of a bad failover? Or is this excessive? Either way, I'm going to do the operation immediately following a full backup cycle.
How would you monitor the failover as it happens? Is the brocade 200e going to log it in detail? I want maximum assurance that everything is still working when I pull those plugs. I can rescan storage on the esx hosts and watch exchange's powerpath monitor. Anything better I can be doing?
I'd rather be far more cautious than the situation merits than make overconfident assumptions about doing something like this for the first time, when all our eggs are in this one basket.