VMware Cloud Community
Sumico
Contributor
Contributor

Problems with LFN and transfer speeds/TCP Window Scaling

We have a 1Gb link between two sites. The latency is 19ms. This limits transmission speed to about 25Mbps with the default max TCP window of 64kb. Is there a way to turn on window scaling in 4.1? Does it work better in 5.1 or whatever the latest release is? What are other people doing about this?

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zXi_Gamer
Virtuoso
Virtuoso

Is there a way to turn on window scaling in 4.1?

Well, there are a lot to consider when you say transfer speed.

1. Separate the management, VC, heartbeat networks and vmotion networks

2. Separate the VM Network to a separate vswitch and try to pitch in a load balancing

3. Try to check with  tcp offload as here http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=200892...

4. The transmission speed is again based on the levels of nic speed and routes, it will not change much to a higher number if you have 5.1

5. Check the possiblity of 10G card which is supported vastly in 5.1

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zXi_Gamer
Virtuoso
Virtuoso

7. And of course Jumbo Frames Smiley Happy

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