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NIC Teaming killing SMB3.0 multichannel

    Question

  • Hello

    I have a situation where SMB3.0 Multichannel is ceases to function after I have teamed NICs yet it functions perfectly beforehand. The NICs have been teamed using the default settings, switch independent and address hashing and I can replicate this behaviour by creating/deleting the team and observing file transfer speeds and NIC utilization counters.

    without being able to provide any diagnostic information at this moment, would anyone be able to shed some light as to what might be wrong or what information I need to provide to help diagnose this? After all multichannel was supposed to 'just work' right?

    thanks

    Friday, June 21, 2013 7:44 AM

All replies

  • No further help?

    This is a fresh install of Server 2012, and the NICS are not part of any Hyper-V  switch (the role is not installed)

    I have followed the troubleshooting steps in Jose Barreto’s blog (http://blogs.technet.com/b/josebda/archive/2012/06/28/the-basics-of-smb-multichannel-a-feature-of-windows-server-2012-and-smb-3-0.aspx)

    Get-SmbMultichannelConnection displays a result for the connection between the 2 servers whilst in a team.

    This works fine whilst the NICs are not teamed?!

    Thanks

    Tuesday, June 25, 2013 4:34 AM
  • It appears that perhaps it might be the switch which is blocking this, if I bypass the switch (Cisco) and directly connect the NICs together with crossover cables this works.

    Tuesday, June 25, 2013 5:01 AM
  • It appears that perhaps it might be the switch which is blocking this, if I bypass the switch (Cisco) and directly connect the NICs together with crossover cables this works.

    A moderator marked this as the answer, however I would like to ask if anyone can shed some light as to what this might be?

    Tuesday, June 25, 2013 10:16 AM
  • can i ask how you set this up before with out the nic's being teamed, as I couldn't access the server if I allowed 1 machine to have a dedicated ip and the other 3 to take ip's from dhcp the server then because inaccessible. 
    Tuesday, June 25, 2013 1:20 PM
  • SMB multi-channel requires that each NIC be on its own network.  Windows doesn't like multiple NICs on the same subnet - it tends to use only one of them.

    .:|:.:|:. tim

    • Proposed as answer by VR38DETTMVP Sunday, October 27, 2013 11:53 AM
    Tuesday, June 25, 2013 10:32 PM
  • can i ask how you set this up before with out the nic's being teamed, as I couldn't access the server if I allowed 1 machine to have a dedicated ip and the other 3 to take ip's from dhcp the server then because inaccessible. 

    It takes a little while for DNS to sort itself out once I create/break the team, have you tried accessing the server via one of it's IP's? I didn't do anything special, the NICs just had DHCP assigned IPs all in the same subnet.
    Wednesday, June 26, 2013 12:16 AM
  • But then you can't run it over a nic team since both vNics can end up on the same switch port effectively limiting your throughput (happened in my setup)? This is very poorly documented, MS don't list different subnets as a requirement for multichannel.
    • Edited by Molotch Saturday, October 26, 2013 10:40 PM
    Saturday, October 26, 2013 10:38 PM