UCS 6100/6200 and Storage arrays

[sumesh.nair]

Can a Storage array either FCoE capable or native FC be directly connected to the corresponding ports on a UCS Fabric Interconnect 6100/6200?If yes are there any limitations and would answers to both the above questions hold true even when we are speaking about Storage arrays directly connecting to a Nexus5K?

there is a lot of ambiguity on the same..would help if Cisco comes out with a positioning statement on this...

[David.Jarzynka]

You can connect fiber based storage directly to UCS but there are some Caveats. The UCS 6100 series cannot provide zoning capabilities for fiber based storage. With that being said, you must use an MDS or Nexus 5K to provide zoning via ISL. If you do not use another device to zone fiber storage, you must use LUN masking on the storage platform side or provide VSAN masking on the UCS side thus keeping the storage LUNs seperate from each server.

I prefer Zoning on a 5K or MDS. Its the standard practice and makes mamagment much easier from a storage prospective.

My 2 cents,

David Jarzynka

[simon.geary]

As of the 1.4 firmware release, compatible NetApp and EMC arrays can be directly connected to the fabric interconnects using either FCoE or FC. Direct connection of other vendor arrays is not supported.

Within the last couple of weeks, Cisco changed their support stance to say that it is now mandatory to have an MDS or Nexus 5k connected to the fabric interconnects for zoning. Default zoning without MDS\Nexus is no longer an option due to some technical issues they discovered. Of course if you need to add an MDS\Nexus into the mix anyway you may well ask if there is any point in using the direct attach feature to begin with. I'm not too sure there is at the moment. So until zoning becomes possible directly on the fabric interconnects I would seriously consider what benefit you are gaining from direct attach.

If you are connecting the storage to a Nexus 5k then you are not using the direct attach feature to begin with so am a little unsure what you mean in that part of your question.

[sumesh.nair]

Thanks Guys !!!

I am referring to a UCS C series scenario wherein the rack servers are connected to a Nexus 5k and since the 6100 is pretty much like the Nexus5K I am just wondering whether a storage array can be directly connected to that Nexus 5K as well

Rgds

Sumesh

[simon.geary]

So when you are using C-Series servers with UCS manager you connect the servers directly to the fabric interconnects, not to the Nexus 5k.

In that scenario you can indeed attach the SAN to the Nexus 5k, and in turn connect the Nexus 5k to the 6100s. You just need the appropriate storage license and expansion module on the Nexus and it will act much like an MDS switch.

If you are connecting C-Series servers to Nexus 5k then the same thing is true, Nexus 5k can be used as the SAN switch. However this scenario does not involve UCS Manager or the 6100s at all.

[Jeremy Waldrop]

What is the issue? We have a customer that is has their EMC CX4 direct attached with no MDS/N5K in the mix. They only have 4 blades but so far no issues.

[simon.geary]

During the recent partner update webcast the problem was blamed on boot storms causing loss of service when many blades try to boot up at once. I never noticed an actual figure that defined 'many'. The speaker said this was a problem inherent in any design using default zoning and not a specific UCS fault. An FAQ on the change is here: https://communities.cisco.com/docs/DOC-24197

I guess this is just one of those theoretical problems that you won't encounter with only four blades. However as Cisco have officially withdrawn support for default zoning we now need to factor this in to designs.

[Radek Kubka]

Did they try doing storage processor fail-over?

E.g. NetApp doesn't recommend default zoning - reason being, apparently controller fail-over takes ages.

Regards,
Radek