Cisco UCS moving to MDS switches

[jn242]

I have a couple of questions. Ill try and keep this as breif and simple as i can. 

I have a UCS System that currently uses a 6332-16UP FIs. Right now it is connected to some legacy non cisco FC swtiches and legacy storage arrays. 

We have new FC storage and are wanting to get some MDS switches. 

My thought is we can cable and configure both the new storage and MDS switches in the same FIs and then migrate all the vms over to the new storage. One migrated over we just decomm and remove the legacy storage and non cisco fc switches leaving the new MDS switches and new storage array. 

Is this supported, meaning have 2 sets of FC switches and essentially 2 fabrics connected to the Fabric Interconnects? I assume this is not a problem but thought id ask. This seems like the simplest way to replace the legacy hardware with the least amount of interruption. 

My second question is about cabling the MDS to the FIs. 

If i have more than one uplink (cable) from the FI to the each mds do i need to create a F Port channel or can i leave them as separate links?

I dont see the need for the port channel as we will never need more than one links worth of bandwidth from what i can tell.  

If i only do 1 uplink from each mds to each FI i will still have A/B redundancy so the only real reason i can see to run more than one link is for failover or increased bandwidth in the case of the port channel but it shouldnt be needed.

IN that case, yes you can run only 1 uplink between each FI and each MDS and it will work without issues but it is recommended to have more than one for redundancy. Is that accurate?

Im thinking i can get away with running 1 uplink from the MDS switch to the FIs and it will work just fine and help keep it as simple as possible giving up some redundancy per FI but still having redundancy through the second FI and MDS link. 

I cant find any clear guidance here. 

If this is not the correct forum for UCS or FC discussions please move it to where it is. Its impossible to find the correct area on this site. 

[jvdmade]

Hi JN242,
You can connect the MDS next to the other brand FC Switch on the FI.
The best practice is to have different VSANs to the MDS.

The second question is personal choice. Personally I like working with port-channels even if there is only 1 link in it.
The big advantage is that you can expand the port-channel with another link with minimum interruption.
If you think 1 link to SAN-A and 1 link to SAN-B is enough for your environment, you don't have to create a port channel.
When one link is failing, the other will take over.
Make sure you total amount of traffic can go over one site, because SAN-A and SAN-B are active-standby.

Kind Regards,
Joost van der Made
Compute Fabric Technologist (TME)

[jn242]

Thank you for the reply. IF it is best practice to have separate VSAN ids in the the MDS fabric, will need additional VHBAs in each server that get zoned to these new VSAN ids?. Wouldn't the VSAN ids need to be the same so the current VHBAs can talk to both storage fabrics? I guess I'm not understanding that part.  

[Matthew Faiello]

You would Cable your FI-A to MDS-A, and FI-B to MDS-B....No FC Cross Over (unlike Ethernet Uplink connectivity to TOR) so each FI-Fabric Pair can have their unique VSANs. This is Best Practice, and reflected in any UCS-CVD.

The Cross-Over cabling occurs between the MDS Fabric Switches and the Storage Array Controllers.

[jn242]

right....i understand not to cross the FC cabling from the A and B side. 

Im mainly wondering if you can run the same VSAN ids in both fabrics to allow vhba0 and vhba1 access to both simultaneously or if i will need to add another pair of vhbas and use separate vsan ids for the other fabric.