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NPV uplinks and portchannels

Hello all,

I am relatively new to storage and FCoE, but i am currently testing FCoE with N5500 and B22HP FEX. And i have two questions:

[1] Using the traffic-map feature, i can assign a server to a specific uplink or list of uplinks. However, what i am missing from this feature, is to give some sort of preference to certain uplinks in the list of uplink interfaces. In the version i am running, if you only select one uplink interface, the server is statically pinned to that uplink. If it goes down, the FC connection goes down. If i give two uplink interfaces, i cannot give preference to one  uplink or the first uplink in the list. Therefore , it is impossible to distribute the load of for example 4 ESX servers across 2 uplink interfaces, while still keeping redundancy in case one uplink fails.

[2] Today, my uplinks are individual NP links to a native Brocarde/HP storage switch. Servers are distributed across these uplinks using an algoritm, but when an uplink fails, the server has to switch to another uplink and this switch is disruptive. I have read that you can fix this by configuring the uplinks in a san-port-channel, but i have been unsuccessfull in setting up a san-port-channel between a Nexus5500 in NPV mode and this Brocade/HP storage switch.I don't know anything about the Brocade switch, and the only port option that i can see is "enable/disable" trunk mode, but i don't know if this means port-channel-mode in Brocade this actually possible ?



Cisco Employee

Re: NPV uplinks and portchannels


[1] Using static traffic-map there is no redundancy, is the uplink interface goes down the interfaces pinned goes down as well, this is how pinning works. If you are using automatic uplink selection the interfaces are automatically redistributed (of course it's disruptive). Anyway, the auto-load-balance feature seems good, it does automatic load balance and is recommended unless if you really need do traffic engineering.

[2]The san-port-channel is a good solution is this scenario, but unfortunately it is only supported in the Cisco platform. Not supported with brocade port-channels.



VIP Green

NPV uplinks and portchannels

Just would like to add a caveat regarding 2)

if you have e.g. 4 uplinks from between a NPV node (N5k, UCS FI) to a Brocade, and eg. 3 out of 4 links fail, then a new flogi will establish a new session over the remaining link. However, once the 3 failing links are coming back again, there will be no redistribution of sessions. This is a differerntiator to the port-channel-trunking between a Cisco NPV and a Cisco NPIV device.

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