9124 Fabric Configuration

Question

I have a very basic question from an obvious rookie...

We are playing with a pair of 9124 switches. When I installed Fabric Manager (3.2(1a)) and tried to discover the network, it found both the switches, but on individual fabrics. The configuration would be much simpler if the switches were on the same fabric, but I have not been able to find a way to change the configuration.

Any suggestions??

jimkunysz · Accepted Answer

ISL - inter-swich-linkIt's a fiber connection using a port from each fiber switch/director and connecting two switches together. similar to an uplink connecting two ethernet switches together.the upside is you can expand an existing san with smaller incremental costs but the downside is each isl connection requires a port on each switch. To be redundant, you would have 2 isl links between two switches/directors. GBIC's fail and if your storage arrray ports were on switch 1 the host ports were on switch 2 and you lost the single fiber cable connection linking them together, your hosts would lose their san disks.

ConnectrixHelpe · Answer

Hello,Are the two switches ISL'ed together? Is the ISL port a TE port between the switches?Thank you.

sandman19 · Answer

No, they are not. I guess I had better do some reading to find out what an ISL is, right?

sandman19 · Answer

thanks for your help. I created the link between the two switches and it seems to be what I was looking for.

AranH1 · Answer

Usually you want to have separate fabrics (separate physical and logical infrastructure) to provide redundancy, did you want to create a single unified fabric?

RRR · Answer

Are you sure you want to connect both switches together ? Connected they form a single point of failure (SPOF), at least when VSAN's in both switches merged into a larger fabric, thus having VSAN x on both switches. Only last week the unthinkable happened to a customer of ours. They interconnected 2 switches and got some VSAN merge. No problem there, but then they changed a zoneset config on switch 2 and on switch 1 all existing connectivity was lost.
I suggest, like many others, you keep both switches separated to avoid a SPOF.

In the magical world of SAN's it's a common rule to connect hosts using 2 HBA's, each to another fabric for redundancy. If 1 path fails, the other keeps on working and data corruption is avoided.

But if you actually DO want to interconnect 2 or more switches, you'd connect them, possibly set the port type from "F" to "E" or leave it at "auto". Usually you'd set the allowed VSAN's on the ISL to only the VSAN's that need to cross the ISL's. And if bandwidth is an issue, combine more ISL's into a portchannel. Set ubnused ports as being a member of VSAN 4094, ISL ports in VSAN 1, don't allow VSAN 1 on ISL's. And please: shut down unused ports and insert the rubber plug into the SFP to avoid dirt landing onto the Rx and Tx. And another thing: have unused fiber patch cables protected with the little white plugs on each fiber as well. Most people don't know what dirt can do to a data connection.

RRR · Answer

Take a look at https://forums.emc.com/forums/thread.jspa?threadID=80533&tstart=50 as well.

sandman19 · Answer

Thanks for the information. I was trying to simply the configuration, but had not considered the potential single point of failure. Thanks for helping me avoid possible problems in the future.

Connectrix

9124 Fabric Configuration

Was this post helpful?