How many FC connection for Continuous Access

[Karol Michaliak]

How many FC connections are necessary for redundant connection one XP512 to another one using CA? By connection I mean FC pair. I thought, that it is two, but somedy told me, that it is four because the communication is divided for data and acknowledge parts. What are your recommendations?

Thanks,
Karol

[Peter Mattei · Accepted solution]

It depends!
The replication works unidirectional per FC link. So, if you want to replicate from one XP512 to another only but with redundant paths, 2 links are OK.
If you want to replicate bidirectional, you will need 4 FC connections.
Another thing to remember is that 2 ports on a XP512 CHIP share one microprocessor. So always two ports have to be set to either Host Target, CA Initiator or CA Target mode.
This means that you will need a full 8-port CHIP in order to do redundant, bidirectional CA. You will only connect 4 and leave the other 4 unused.
See the attached drawing.

Cheers
Peter

[Karol Michaliak]

Peter,
only one additional question. Is this 2 port sharing true also for 2Gb CHIP for XP512?

Thanks,
Karol

[Peter Mattei]

Yes, also true for the 2Gbit/s CHIPS on the XP512.

It is different on the XP1024 where you can define it per port.

Cheers
Peter