Excessive HDD access makes machine unusable

[Bulishor]

We're running a number of machines with VM Workstation and different images. Almost all have performance issues due to VM excessively accessing the HDD. When this happens the image becomes unusable until the process is finished and that can take upwards of a few minutes. After it is done, the machine comes back to normal until the next fit.

We're trying to identify the reason why VM does this, whether it is a specific process or some kind of sync between the memory and HDD etc. Are there any settings we should try to tinker with to alleviate this problem?

We're running the latest version of Workstation on an XP host with 4Gb of RAM.

[weinstein5]

Welcome to the Forums - I bet the issue is the number of VMs you are running under workstation - it not designed to host multiple VMs to be accessed by multiple users - I would look at moving the VMs to either VMware Server or ESXi -

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[Bulishor]

Sorry, I don't think I was clear enough... What I meant is that we have a number of machines, each running Workstation. We also have a number of images but we try to only run one at a time on each machine.

[weinstein5]

I understand now - what are the VMs doing and how are they configured?

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[Bulishor]

The images are built on either XP or Server 2003 OS, they have development tools installed such as Visual Studio and they are part of a domain. If you need specific configuration details please ask and I'll do my best to answer.

The VM perform relatively well, with the expected sluggishness of a virtual machine but every now and then it starts accessing the HDD continuously anywhere from a few seconds to a few minutes. We see the HDD light being on and we hear the hard drive spinning like crazy but the VM is unusable. We can switch over to the host and work on it, albeit more slowly.

As far as I know the Player and Workstation use the same virtualization engine, is that correct? Is there any documentation where I can confirm this like a white paper, technical detail etc? My boss would like something formal before we make any kind of switches or buy more licenses.

Thanks in advance.

[CrazyEnigma]

There are a few things that I see would cause this:

VM behaves very similar to the host OS. If your memory usage on the OS peaks past physical limit, the OS will start to page. This is similar in a guest OS. If you have allocated more memory to the VM than there is physical, VM will use paged memory (memory writing to HD) - this is what causes the sluggishness.

• You have to consider hardware resources must not exceed host OS resources + guest OS(s) resources.

Smaller host OS footprint = large resources available to the guest OS.
The three main hardware components to consider are:

• CPU

• Memory

• HD - then there are HD spin speeds, I/O bandwidths to consider* The second thing to consider is whether your VM has any services running you don't know about. From your question, it is unclear what action you did when the thrashing started. Check out if there are any services like Anti-Virus, Backup running on the VM. These things aren't necessary.

• The next thing is whether you are running multiple VM. If this is the case, then the I/O bandwidth would come into play more.

• Finally, if you are attempting to run 64-bit guest OS on a 32-bit host OS, you will have serious problems, because now the host is working twice as hard because the I/O bandwidth is constricted.