Server has long %ready time and %cstp problem how to resolve it

[MrHoek]

​Dear Users,

We have a critical ESXi host with important VM's but we are noticing a slowdown on our network and on the server it self.
So I have begun investing the problem and noticed that one server on the ESXi host has a high %ready time, see picture 1 below. 13855 / 20000 = 0,69275, which makes it 69% ready time.

The server has the following configuration, see picture 2 below.

After this was clear to me I monitored it with ES​XTOP and saw that I have a high %cstp on one server, see picture 3 below, this indicates a high vCPU use but the server has only 2 vCPU's.

Now I was wondering do I need to reduce the Number of virtual sockets or do I need to reduce the Number of cores per socket?

Or do you people think its better to reduce the Total number of cores?

The server is a critical application server where loads of traffic goes true.

Kind regards,

Martijn

[jjlp]

Im just following, I have the exact same problem.

Im running ESXi 5.1 on a IBM x3550M4 with 7 citrix servers with each 2vcpu.

the Ibm server has 2 x 2.9GHz E5-2690 processers and 8 cores each. the 7 citrix VM are running on local storage on 4 sas HD in a RAID 5 configuration

So i am also interrested if there is anything to eliminate this.

Im baffeld because there should be cores enough to support each VM so that each VM get one physical core

Kind regards

Jesper

[MrHoek]

Dear jjlp,

I have solved this problem within our organization, I have managed this by doing the following
1. Remove the E1000 network card
2. Install the VMXNET 3 network card ( You need to have VMware tools installed on the server for the network driver)
3. Increase the Number of Virtual Sockets, by increasing this I had 4 Number of virtual Sockets
4. Decrease the number of Number of cores per socket, by decreasing this I had 2 Number of cores per socket
5. After this I have monitored our VM with Visualesxtop ( VisualEsxtop – VMware Labs )

After this the problem was solved
- Why change network card type?
1. E1000, E1000E and VMXNET3 performance test | Ramses Smeyers
2. Continue to world of virtualization: What’s faster E1000 or VMXNET3 – let&#8...

Conclusion: By using this new network card the CPU use is lower
Tip: Make sure you delete the old E1000 network card in the device manager before disabling it or else you will have ghost network cards

I hope I have answered your problem?
If you need more help resolving this issue please let me know.

Kind regards,
Martijn