we have a really strange netapp snap mirroring issue that came up after me made some changes to the nexus 7000's in our data centers. we have 2 data centers. dc1 has 2 n7k's and dc2 has 1 n7k. we had them connected thru a single 10gb link. a few weeks ago we added a second link and setup the links as a port-channel. vpc on dc1 end and regular po at dc2. we also have 2 netapp controllers in dc1 and 2 in dc2. after we did this the snap mirroring became very slow form 1.2 gb to 90mb. but this just occured when it went over 1 of the data center links using dc1 n7k-2. we tried shutting down and reversing the links but the problem seemed to follow the dc1 n7k2. we then frorced everthing over dc1 n7k-1 and we had the same slowness issue. we then decided to move the connect in dc2 n7k-1 from slot 4 to slot 1 (where the other connection is) and it resolved the issue. both modules are m1 10gb series cards (no differences between the cards). we had already opened a tac case with cisco (626790461 : slow data transer between n7k's using 10gbase zr optics). they send us a new module for slot 4. we installed it and the same problem. we moved the module to slots 3, 7, 8 and the same problem. the only way we can get this to work is to have the port-channel in dc2 have both interfaces on the module in slot 1. we also opened a case w/ netapp and they are saying it's a network issue. we have tried everything we can think of to resolve this issue and nothing seems to work.
any help would be greatly appreciated. thank you.