VMware Server performance issues

I have a server which is co-located in a data centre.  The server OS is Ubuntu 6 (Dapper Drake I think).  On the server I have installed VMware Server 2, and I have several VMs running on the host.  The VMs are all Windows Server 2003.

My problem is that when I get a remote desktop to any of the VMs, everything works fine for a few minutes, and then for no particular reason the VM slows down dramatically.  Even the clock slows down so that it falls behind the real time.  For example, 5 minutes real time can elapse, but the clock on the VM will only show 2 minutes elapsed.

When I look at SysInternals Process Explorer on the VM, there isn't any one process which seems to cause the slow down.  Sometimes the Explorer process is using CPU, sometimes it's TextPad; occasionally the Interrupts or DCPs processes seem to be using a lot of CPU.  But even when nothing is using excessive CPU or memory, the VM seems to be in slow motion.  The clock slows down; when I switch between windows it can take 15-20 seconds to do so.

Any ideas as to what might be causing this?  It happens on all the VMs, not just one of them.
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vmwarun - ArunCommented:
What is the hardware config of the Ubuntu 6 Server ?
mrgordonzAuthor Commented:
Asus RS100-E4/PI2 rack server
2 x Intel(R) 6320  @ 1.86GHz
500 GB HDD

There are currently 3 VMs running:

VM1 - 2 GB RAM and 50 GB HDD
VM2 - 2 GB RAM and 35 GB HDD
VM3 - 1 GB RAM and 30 GB HDD
za_mkhIT ManagerCommented:
Of course what is happening here is affecting all VM's so the issue is definitely not guest related - it has to be something on your host. Now I personally don't like VMWare Server 2 ... something about it is not written well ... I prefer to stick to VM Server 1.0.x
But some experiences I've seen with VMWare server 2 seem to go away when the host server is restarted - like it's a memory/CPU issue? Is that something you can try / have tried?
I would recommend you replace your host OS with ESXi for better performance (unless of course the Host Server is being used for other purposes too)...

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mrgordonzAuthor Commented:
Hi za_mkh,

Yep - I can definitely restart the host server.  

Funny you should mention ESXi - I am in the process of investigating replacing VMware Server 2 with vSphere 4 which I believe includes ESXi (or ESX).  I'm not sure as to the difference between ESX and ESXi.

I have never actually used or installed ESX (or ESXi).  Assuming I replace the current host OS with ESXi, do I need to do anything to the VMs to make them work?  Also, what would be the process for replacing the host OS.  I'm guesing it would be something like this:

1. copy existing VMs (and other data) on to an external disk
2. format the host hard disks
3. install ESXi
4. copy back the VMs

I have several ISOs which are on the host server that I use as virtual CD/DVD drives.  Can I still use them?


za_mkhIT ManagerCommented:
ESX and ESXi both share the same hypervisor ... which is the important bit!  But ESX is the 'paid' for version of the Hypervisor which includes the Service Console.ESXi is the free version with the same Hypervisor without a service console.
Functionality is nearly the same and in fact, ESX will become redundant in 2 years time, when ESXi become the 'defacto' hypervisor platform
If you do replace use ESX or ESXi then you can use vCenter Converter 4 (which is also free) to convert your VMServer VM's to an ESX format VM's. Really trouble free and works like a treat!
So in your steps, once you have copied your VM's from the host, you then install ESXi (which will format the drives). Then using vcenter converter on your laptop and tell it to convert the vm's from your external drive directly onto the ESXi server! Really is that simple.
Just one word of warning. Make sure that all the components of your Host server is on the ESXi hardware compatibilty list. Sometimes it has issues with SATA controllers, etc.
za_mkhIT ManagerCommented:
If you do replace use ESX or ESXi then you can use vCenter Converter 4 (which is also free) to convert your VMServer VM's to an ESX format VM's. Really trouble free and works like a treat!
was supposed to read
If you do use ESX or ESXi, then you can use vCenter Converter 4 (which is also free) to convert your VMServer VM's to an ESX format VM's. Really trouble free and works like a treat!  
mrgordonzAuthor Commented:
I'm not sure if it has actually resolved the issue, but I have noticed the VMs respond better.  But the clock still slows down.  I have decided to upgrade to ESX and be done with it.
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