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daf
Contributor
Contributor

ESX 3 support for TCP Window scaling?

Hi all,

we're currently doing a migation of (physical) application-servers from remote offices to VM in the central datacentre. We're using VMware Converter 3 for this.

One thing we noticed during the conversion is that we're only able to transfer appr. 6GB/hr over the 1Gbps WAN-link.

A way to improve this is the Wintel world would be to use TCP Window Scaling (RFC1323)and set a seriously TCP high Receive Window.

Question now is: does ESX 3.0.1 also support such Receive Window scaling and if yes, how/where do we configure that?

Any help appreciated.

Michel

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3 Replies
dsidler
Contributor
Contributor

Michel

Did you get this answered somehow? I'm running into the same problem when moving VM between locations over a T3 with 35ms latency.

Dan

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kgilbert
Contributor
Contributor

i am interested in this as well...

-ken

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Paul_Lalonde
Commander
Commander

Hey.

Both the VMkernel and the Service Console support RFC1323, but you can only configure it for the Service Console.

When using Converter, it's the ESX Service Console that handles the network I/O, not the VMkernel. So, normal Linux TCP/IP stack tuning (via sysctl.conf) would apply here. The difficulty would be finding the optimal bandwidth x delay product value for your initial TCP window size. Have a read here:

http://www.enterprisenetworkingplanet.com/nethub/article.php/3485486

Good luck!

Paul

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