Network Storage Protocols Discussions

MultiHop FCoE



I have a question regarding FCoE we have FCoE local in the datacenters with cdot clusters serving lun's this works great. But now we need to access lun's on an other cDot cluster on a remote site we've got FCoE over the sites in place server sees the LUN's but when putting a load on it we get FCPIO_DATA_CNT_MISMATCH.


The local config that works is AFF 8040 -> Nexus 5000 -> UCS


The config that's giving issue's is AFF8040 -> Nexus 5000 -> Nexus 7000 -> WDM -> Nexus 7000 - Nexus 5000 -> UCS.


Is there anyone who's having experiences with this kind of config.


Thanks in advance,




Re: MultiHop FCoE

Hi Sebastiaan,


We do not have that config, We are running FCOE local but from the Nexus 5x switches we do: UCS - Nexus - MDS - DWDM - MDS - Nexus - UCS.

Do you not get any data over the link or is it when data you stresstest it?





Re: MultiHop FCoE

Hi Arnold,


We've link between host and storage and the storage is readable writeable. But it's not stable even with a small load paths fail and come back everytime the higher the load we put on the more we see the links fail and come back.





Re: MultiHop FCoE

Hi Sebastiaan, hope you've resolved this issue by now, if not...


I understand this error is due to the frames being received out of order - possibly a hardware issue or flow control between the switches.


To confirm for Cisco switches FCoE is supported up to 7 hops (up to 3 of the switches can be FCoE switches), i.e. # of switches between your storage and host.


Hopefully this helps.




Re: MultiHop FCoE

Hi All,


An late update on the this issue. We finally got an statement from cisco that the current configuration as we have isn't supported for the distance we have. So we need old school FC swicthes between our datacenters.



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