Maximum number of Fabric Interconnects in a Cluster

[sidranx.shu]

I work for a Demo department that sends out Cisco 6248's with 5108 Chassis with various B-Series Blades, we are currently brainstorming setting up a live UCSM environment with a UCS environment pre-configured with templates to update B and C Series Servers.

I am wondering if there can be 3 6248 Fabric Interconnects in a single cluster?  Or a way to connect a stand-alone configured 6248 and update 2 6248s from it?

[richbarb]

Hi sidranx.shu,

The UCS Fabric Interconnect 6248 can be deployed only in pair or standalone. Three 6248 in one single UCS domain is not possible.

You can use two 6248 as your UCS domain and you will have full redundancy of all. Turn on the third FI might not be a advantage if high availability is your requirement, since it will run as standalone.

Be aware that you can connect up to 20 chassis in one single pair of Fabric Interconnects.

Maybe this document can help you:

http://www.cisco.com/c/dam/en/us/td/docs/solutions/CVD/Aug2013/CVD-UnifiedComputingSystemDesignGuide-AUG13.pdf

Regards,

Richard

[sidranx.shu]

Richard,

Thank you for your response.  HA is not a concern since we are only testing basic functionality and updating FW.

The main goal is to have a UCS Domain setup at all times so that the initial configuration would only have to be done once and be able to update units and ship.

If I connect another pair or standalone 6248 to the active USC Domain, would that domain be able to see the new 6248s and be able to update them?

[richbarb]

Hi,

The UCS domain only work in a pair or standalone, and each UCS domain is managed independently in the UCSM.

To integrate all the UCS domains you can use the UCS Central, and then perform the FW management in a more concise way.

To know more about the UCS central, please look at:

http://www.cisco.com/c/en/us/products/collateral/servers-unified-computing/ucs-central-software/data_sheet_c78-717193.html

Regards,

Richard

[Keny Perez]

Richard is 100% correct in his explanation.. the reason why you cannot have more than 2 FIs on a domain is because the cluster is formed through the connection of the L1-L1 and L2-L2 ports on each FI; so once you connect the Fabric Interconnect to another Fabric Interconnect, you run out of L1-L2 ports that can be used to integrate a third FI.

I hope that clarifies all possible doubts, if so, please rate the helpful answers and mark Richard's explanation as an answer for any future users having the same questions/doubts.

-Kenny