iSCSI Tuning found something interesting

I have been playing with settings to get better performance with open-e and esxi4 using 10GB dual port cards using round robin. So I first changed the settings on the target and the esx host server too match the following settings:

maxRecvDataSegmentLen=262144
MaxBurstLength=1048576
Maxxmitdatasegment=262144
FirstBurstLength=65536
DataDigest=None
maxoutstandingr2t=8
InitialR2T=No
ImmediateData=Yes

I used iometer and was getting a combined Read/Write of 650MBs which was slower than the dual port 8GB fibre. I then decide to change the round robin iops setting in esx from the default of 1000 to 1 for the iscsi volume. I ran the same test and now am getting 879MBs. There is a lot of information about this in the vmware forums and certain vendors recommend changing this settings lower, i was just wondering if open-e has any information on this.

Gavin

Hi Gavin,

We do have information about this and the steps to make this work with the ESX 4.x from the link below. These are good points you bring up
to help others, thus the link below to give the steps to make these changes on the ESX side.

http://www.open-e.com/site_media/dow..._ESX4i_4.1.pdf

Thanks for that never used that document, one other change that is recommend by vmware and hp is to change the Disk.DiskMaxIOSize to 128 KB on the esx host in the advanced settings. So far everything is working great with all these settings, what benefit would Jumbo frame give?

Thanks

You might see a bump of 3-6% hard to say as I cant nail down the exact numbers due the amount of variables.