Slow networks in ESX3.5

[matt4130]

Afternoon All,

We like to get the most out of our kit and we are currently running about 85% CPU Utilisation and 80% Memory utilisation across 3 clusters in our environment. 2 clusters contain 4ESX hosts and 1 contains 8. I have rearranged our resource pools to keep everyone happy for the time being, but i am still getting terrible network performance between the machines. Whether they are on different hosts, the same cluster, different cluster, different hosts!

I think it's simply contention on the hosts, but I wondered if anyone had any ideas?

Matt

[weinstein5]

Does the networking performance get better as CPU utilization drops? I think what is happening is that your CPU utilization is so hight that it is impacting the vmkernel's ability to provide a virtualized network

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[matt4130]

Ha ha! This is the problem. I don't know what happens when the CPU utilisation drops, it never does!

I think you're right about the kernel. If the CPU's are being hammered then you're going to see problems.

[weinstein5]

Most people forget that the vmkernel needs some cycles as well -

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