topic VC Fibre Modules in BladeSystem - General

VC Fibre Modules

Tom Nagle — Wed, 04 Feb 2009 21:52:50 GMT

We have two virtual connect modules in a C7000 enclosure and the enclosure is full of half height and full height servers. How do I have to arrange the servers if at all to use 2 of the 4 connections for 1 SAN and the remaining two connections for another SAN and present disc to both. These are two different fabrics in our environment.

Thanks,

Tom

Re: VC Fibre Modules

Adrian Clint — Thu, 05 Feb 2009 01:10:15 GMT

Tom,

Following assumes you are using a multipath utility......

Servers can only map to one SAN via two VC fabrics (you may call them 2 paths on 1 fabric - but VC calls a path a fabric - is that whats causing a confusion?)

You can have two different SANs to an enclosure but servers can only connect to one SAN a a time. (using a single
OR.............................

You could use another set of VC-SAN modules but I'm assuming you cant get them to fit.

OR............................
You could connect one SAN to one VC-SAN and one to another. Two SANs but only single path to each.

Re: VC Fibre Modules

The Brit — Thu, 05 Feb 2009 12:04:27 GMT

Tom,
Your question is a little confusing, however, as Adrian pointed out, the four ports on a single FC VC module should only be connected to 1 SAN fabric (say SAN_A), which provides four paths to that fabric. You can, if you wish, define the individual ports as separate SANs (within VC), i.e. (Port1 =)SAN_A1, (Port2 =)SAN_A2, etc., and then you can control which servers talk thought each port (to spread the load). (I dont believe the FC modules load balance on their own).

To use both fabrics, connect the 4 ports on the 2nd FC VC module to Fabric B, (i.e. SAN_B. This, in and of itself, does not mean that fabric B is being used, however it does provide failover in the event that your other FC module fails. Notice that if throughput is important to you, you could configure the 2nd module similar to the first (i.e. create SAN_B1 - SAN_B4) and assign the HBA ports directly to specific internal SAN definitions (within the server profile), i.e. under the SAN section, assign HBA Port 1 to SAN_A1 (say), and HBA Port 1 to SAN_B1.

Your multipathing software should then deal with path-switching in the event of connectivity issues.

A more important consideration however, (and this may not be what you are talking about), If you have a mixture of Full and Half-height blades, and only one dual port HBA in each server, then the HBA must be in the same Mezz port on all Servers and the FC VC modules must be in the appropriate IC bays. i.e. Mezz 1 maps to IC3 and IC4, and Mezz 2 maps to IC5 and IC6. Mezz 3 is only applicable to Full height blades.

Hope this helps.

Dave

Re: VC Fibre Modules

Tom Nagle — Thu, 05 Feb 2009 18:03:24 GMT

Thank you, we have also contacted support and the new version has the ability to allow us to connect VC to two different SAN's but will need to flash the VC firmware to 2.01.

I appreciate the responses.

Re: VC Fibre Modules

Adrian Clint — Thu, 05 Feb 2009 20:26:56 GMT

Tom,

With the new firmware you will be able to have 2 SANs to the enclosure. But the odd numbered blades will connect to one SAN and the even numbered blades to the other.