Sudden decrease of VM performance

[zgz87]

Hi all,

I am quite a newbie with vmware ESXi and today something strange happened to me. I am running only one VM for test purposes in one host. This VM uses Windows server 2003 as the OS. I have been working with that VM for weeks without any problem. I usually open a Console with vCenter to work on it. Today, suddenly, the mouse inside the VM started to go really slow and at the end I could not even move it. If I clicked something it took around a minute to actually click inside the VM. I powered it off and on and it took almost 10 minutes to boot! (normally it takes less than a minute). I have been checking in vCenter the performance and everything is normal and no limits are reached.

If that same VM is migrated to another host, everything works perfectly, without any problem. As soon as it goes back to the previous host, it is annoyingly slow. I tried to ping it to check if the network was the problem but I get 1 ms of latency. The storage should not be the problem since I am accessing to the same storage in both hosts over the same ports.

Does anyone have a clue what could be happening or where should I look to get more information?

Thanks!

[rickardnobel]

If you open a RDP session to the VM and keep that session open while vMotion in and out of the specific host, how is the performance?

[zgz87]

Hi RickardNobel,

Thanks for your answer but I can only perform cold migrations so I must turn off the VM. Therefore, I cannot really check if suddenly the performance increases after moving the VM. What I can tell is that in one host the VM works correctly, in the other really slow.

[rickardnobel]

Just a sidenote: you have vCenter, but not vMotion setup, is that correct? Do you have license for the vMotion feature?

[BharatR]

Hi,

Check Your host may have CD-ROM autoplay enabled. You should disable that  functionality.

Secondly Uninstall the VMware Tools and Reinstall it again and Confirm

[zgz87]

I have both, the problem is that the hosts do not belong to the same cluster, that is why I cannot use vMotion.

[rickardnobel]

But does this VM work good inside the Cluster that it belongs to?

[zgz87]

No, the VM works slow in the cluster it belongs to.

[rickardnobel]

zgz87 wrote:

No, the VM works slow in the cluster it belongs to.

On all hosts inside this cluster? While other VMs on the same hosts work fine?

[zgz87]

The other VMs in that host also work very slowly. The cluster is composed of only one host (the tests we are doing require only one host per cluster). Anyway, I have just moved the host to another cluster (the one where the host working normal is placed) and the same behavior is appearing. Therefore it does not look like it is a cluster problem.

[rickardnobel]

It does seems like a problem related to this specific host. Have you checked out some key performance values, like CPU load, memory consumed and similar?

[zgz87]

Yes, I ahve been checking all that in vCenter (performance tab). Everything looks completely normal. I was wondering if I may get some information in logs. I was checking vmkernel.log but nothing really interesting appears there. Do you have any idea where in ESXi could I find some information that could help me discover where the problem is?

Thanks again

[msundling]

This KB has information about all ESXi 5 log files: http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&externalId=2004201

If you look in Windows Event Log in the VM, do you have any suspicious warnings/errors?

/Mattias

[zgz87]

Thank you!

At the end the problem was in the network side. One of my switches was misfunctioning and that created these delays.

[rickardnobel]

zgz87 wrote:

At the end the problem was in the network side. One of my switches was misfunctioning and that created these delays.

Nice to hear that the problem was resolved and thank you for notifying the Community of the solution.

[msundling]

These problems that are outside of the hypervisor are always hard to get to. Nice that you finally identified the problem.

I can recommend a FREE tool called vOPS Server Explorer.

It will detect the most common Performance, Capacity and Inefficiency problems in your vSphere environment.

Disclaimer: I work for Quest Software

/Mattias