Do not use Jumbo Frames, Do not set MTU to 9000, Do not collect $200

Post date: Jan 6, 2014 3:36:59 AM

I'm seeing so often storage performance issues where someone has configured jumbo frames somewhere because they were following some best practices guide, but it seems they only did it on the one device who's doc they were reading... or better yet they think that Jumbo frames are so awesome that they should configure them on almost everything. The operative word there is almost. Maybe I am just in the wrong line of work right now but it's depressing. Folks... please remember if you are going to tweak something, it is very important to realize the implications of your tweak. Jumbo frames are great if you have everything on the layer 2 domain configured correctly. If you are doing routing, don't forget to clamp the TCP MSS appropriately before leaving the networks that support Jumbo. In most cases you are only going to get a minimal performance increase with jumbo frames IF you have it configured correctly.