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MD3200i, 5424 - NIC jumbo frame size?
Hi,
Setting up an MD3200i with two 5424 switches in multipath. The server has Intel NICs with only 4088 and 9104 as frame size choices. Subjectively 4088 seems to speed things up and 9104 makes no difference, but I haven't run any benchmarking. I have jumbo frames enabled on the switches from the Dell iSCSI setup document. Should 9104 make a big difference/what setting should I choose?
Thanks
Dev Mgr
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October 21st, 2010 11:00
The "9000" on the MD will allow frames a little larger (9016 or 9014 will be the actual max).
I'd go with enabling jumbo frames on the 5400-series switch(es), setting the NICs to 9014, and setting the iSCSI ports on the SAN to 9000. That combo should work just fine.
Dev Mgr
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October 13th, 2010 12:00
What kind of NICs do you have and what OS, that you only have those 2 choices for jumbo frame sizes?
Normally there are a whole series of choices including 9000 and/or 9016.
dmipg
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October 13th, 2010 14:00
This is Windows 2003 R2 x64 with Intel Pro 1000 PT dual port adapters using the latest drivers from the Intel Web site. The choice is a drop down of Disabled or the two values given above.
Dev Mgr
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October 14th, 2010 06:00
Is that one choice maybe 9014 instead of 9104? I've seen "9000" be reported at "9000", "9014" and "9016" depending on which brand/model switch and/or NIC it is.
mrokkam
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October 14th, 2010 10:00
The important thing with Jumbo frames is to choose a size that is supported across the board. Otherwise, the best that you can expect is that the device supporting the smallest size will split the jumbo frame into smaller frames and you get no performance benefit. At worst, it will discard them.
Verify the setting on the MD3000 and ensure that your NIC and Switch jumbo frame settings are set to the same value
dmipg
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October 19th, 2010 15:00
The other value on the NIC drop down is indeed 9014 and not 9104. The 5424 switch documentation says jumbo frames up to 10K, but the max value on the iSCSI host ports of the 3200i is 9000 so I guess 9014 is too big and I should stick with 4088