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  • 1.  Using jumbo frames over 10Gb uplinks

    Posted Nov 26, 2012 04:32 PM

    I have 2 10Gb uplinks which are carrying NFS, vMotion, virtual machine, and all traffic going to the host.  What is the best practice with regard to jumbo frames?  If I use them to optimize NFS traffic, it affects all other traffic as well such as production VM traffic as well.   Should NFS always use jumbo frames?



  • 2.  RE: Using jumbo frames over 10Gb uplinks

    Posted Nov 27, 2012 10:11 PM

    If you enable jumbo frames for your vmkernel port that carries your NFS traffic, but leave the MTU at 1500 for all other port groups, you shouldn't see any impact on your other traffic. This assumes of course that your NFS traffic isn't going to saturate your uplinks.

    mike



  • 3.  RE: Using jumbo frames over 10Gb uplinks

    Posted Nov 29, 2012 01:51 PM

    OK thanks.  So in that case I am running both 1500 MTU and 9000 MTU frames over the same uplinks.  Can the physical NICs of servers and the ports of physical switches upstream all be configured handle both 1500 and 9000 MTU frames simultaneously?  Are there issues or problems with this?



  • 4.  RE: Using jumbo frames over 10Gb uplinks

    Posted Jan 04, 2013 10:43 AM

    TheVMinator wrote:

    Can the physical NICs of servers and the ports of physical switches upstream all be configured handle both 1500 and 9000 MTU frames simultaneously?

    The MTU is really the maximum transmission unit, which means that for example a physical switch port that is configured to accept jumbo frames will have no problems handling default sized ethernet frames as well.



  • 5.  RE: Using jumbo frames over 10Gb uplinks

    Posted Jan 04, 2013 10:53 AM

    the MTU size denotes the maximum packet size that can be transported,  just because you have set a large MTU size does not preclude you using smaller packets, one word of note is that if you set Jumbo Frames, you need to make sure that your whole environment can support them, Routers, Switches and Servers.



  • 6.  RE: Using jumbo frames over 10Gb uplinks

    Posted Jan 04, 2013 04:08 PM

    Don't forget to also set the actual vDS for an MTU of 9000 in addition to your VMkernel ports.



  • 7.  RE: Using jumbo frames over 10Gb uplinks

    Posted Jan 04, 2013 06:49 PM

    So there are no issues with having some port groups using jumbo frames and others using regular size on the same host?  I just set the rest of the network to allow them end to end?



  • 8.  RE: Using jumbo frames over 10Gb uplinks

    Posted Jan 04, 2013 06:52 PM

    Nope. I have management and storage on the same physical uplinks. Management VMkernel is on 1500MTU and VMkernel for NFS is 9000MTU. Like the others have said, it is just a definition of the maximum transmission unit size. Just make sure the vDS itself and your physical uplinks are also set to support jumbo frames.

    The vDS setting is under "Properties" tab and then "Advanced" .



  • 9.  RE: Using jumbo frames over 10Gb uplinks
    Best Answer

    Posted Jan 04, 2013 06:52 PM

    TheVMinator wrote:

    So there are no issues with having some port groups using jumbo frames and others using regular size on the same host?  I just set the rest of the network to allow them end to end?

    From the ESXi side it should be no problem. Do you have separate VLANs for the different type of traffic? (Management, VM, NFS and other.)



  • 10.  RE: Using jumbo frames over 10Gb uplinks

    Posted Jan 04, 2013 06:56 PM

    Great - thanks again.