To Jumbo Frame or not to Jumbo Frame - That the question..

hi everyone,

currently on windows 2012 r2 hyper-v servers.

network infrastructure switches , nic on san , lan configured handle jumbo frames.

on management, san , live migration network in hyper-v have configured jumbo frames. can test "ping -l 8960 -f ip" , see ping reply.

vm switch configured jumbo frames. i'm 100% sure 99% of guest vm's windows os not configured handle jumbo frames. best practice do?

if jumbo frames configured places on hyper-v host , guest os, make performance worse if remote desktop servers internally lan communication can use jumbo frames, when "talking" default gateway need use 1500 bytes packets..

although not agrees it; jumbo frames can improve network throughput. there things aware of:

• only try enabled jumbo frames on isolated vlan's, used 1 purpose only. such iscsi , live migration vlan's.
• do not enable jumbo frames; if have nic team, used team nic "management" , "cluster".
• do not enabled jumbo frames; if have vswitch used vnic "management", "cluster" and/or vmnics (virtual machines)

so example. enable jumbo frames on e.g. seperate "iscsi" nics. or on seperate "live migration" nics. mentioned isolated, because reason gave yourself. devices in vlan must use same mtu size. if have router interface has mtu 1500, things can go wrong , can complicated.

depending on switch brand/type; most often it not matter if you enabled the physical switch jumbo frames. this only allows switch accept such large frame sizes. devices connected switch frame size use. when going route traffic (on non-isolated vlans) aware that packet defragmentation occurs. this will most decrease performance. 

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boudewijn plomp | iton consultancy

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Windows Server  >  Hyper-V