Paul,  save yourself headaches and future outages, buy some  LC-LC cables and connect additional CX ports to each switch  Switch 1:  SPA0 SPB1  Switch 2:  SPB0 SPA1  at least something like that, fabrics will NOT merge, CX is not an FC router [IMAGE]. If your system admins do not buy Powerpath they can still use native multi-pathing. Your zones would look something like this:  Switch 1:  host1-hba1-SPA0 host1-hba1-SPB1  Switch 2:  host1-hba2-SPB0 host1-hba2-SPA1
I have a relatively basic newbie question, but I'm not clear on how paths work with the two SP inputs on a CX-4. I apologize now if this isn't clear, it's hard to explain.  Currently we have two Brocade 5100 fabric switches in one fabric;  we need them separated as separate fabrics, one switch per, with different zone sets. Our server team doesn't always use multipathing, so it's necessary to have each switch standalone, especially as we're still straddling this new SAN with the old due to a recent migration. Not the best practice, I know.. they know too. But EMC had wired our old SAN that way and everything worked out fine.  Now, as it stands, each switch has just one connection to the CX-4, Switch "A" is connected to SP-A input, and switch "B" is connected to the SPB input.  I would figure we should have each switch connected to both SPs but our data center guy -or Dell- not sure which did the hardware install, didn't do that.  I believe we're out of cables now too, and the state's ordering process will ensure headaches and delays getting them.  Now that I've painted the picture, The Question is this: If a server has LUNs currently owned by SPA, but is connected only to the switch that will be going to the SPB input, then after the separation, will that LUN get cut off without a manual trespass or running failover as AULA mode 4 (active/active)?  Does the SPA input automatically internally talk to SPB without special settings and protocols?  Reason being, all the LUNs are setup right now as PNR mode 1, passive/active.  Another possible solution to avoid this issue is to very simply connect each switch to both SPs, by simply running 2 more cables (when I can get them),  *but* would that cause the switches to see each other (through the CX-4) and join in a single fabric again? Because that would break everything.  I'm hoping this is as simple as running the two extra cables to ensure no server gets cut off from it's LUN, no matter which SP owns it or controls it, while allowing the switches to remain separate fabrics.  Thanks!  Paul
SPA vs SPB paths and failover