Enabling Jumbo Frames ESX3.5

[marsh8]

We have identified a possible bottleneck which may be delaying the transfer of data from one VM to another in the same cluster.

There has been a suggestion that enabling jumbo frames may boost the transfer of large amounts of data between the 2 VMs for a particular process.

I have read:

http://www.vmware.com/pdf/vi3_35/esx_3/r35/vi3_35_25_3_server_config.pdf page 63 + updates.

I am confused by the following statement:

"Jumbo frames allow ESX Server 3.5 to send larger frames onto the physical network"

Given that in our scenario the guests are on the same cluster (and potentially on the same host) would we expect any benefit from enabling "jumbo frames" as described if all the network traffic occurs within the vswitch, or is this all about configuration end to end for network traffic destined for the physical network?

Thank you

[kjb007 · Accepted solution]

The intent of this is mainly for storage type traffic, where your server uses larger blocks for higher speed transfers. You can use it for virtual machine, but if your vm's are on the same vSwitch, then they are not even hitting the server pNic to go out the ESX host to the switch. In that scenario, you should be getting as fast a speed as should be possible.

How did you discover / identify this bottleneck?

-KjB

[marsh8]

The bottleneck was not identified. The conversation was more along the lines of "We've enable jumbo frames for our backups and have seen a benefit for moving large amounts of data. We may be able to use for other apps that move large amounts of data". This was a useful investigation for us. I have put together a procedure for enabling jumbo frames in ESX as part of the discovery.

Thank you

Separately I notice a previous post of yours re: Biztalk

http://communities.vmware.com/thread/195344

Did you get past this?

[kjb007]

Yes and no. We're running several biztalk servers now, but have noticed problems with storage latency causing more of an issue than the preivous memory discussion. Biztalk appears to be very touchy about access times, enough so that I typically will keep my biztalk vm's in manual mode for DRS. Even the loss of a ping or two can cause the app to act flaky.

KjB