20 Windows VM's Slow HDD?

[iTimOSX]

Dear VMWare,

I'm doing a little research with VMware with my trail license.
I now have 20 Windows VM's running.
They all run different apps since I let my college students use them.
Sometimes it's just a XAMPP webserver, other times a gameserver and sometimes both.
When creating more and more VM's I noticed slowdown which is normal ofcourse.
But now sometimes these VM's are very and very slow.
I know it has something to do with the HDD because the CPU is just 19%.
I've attached a screenshot with this post.
I'm just running one server with one HDD (2TB).

I hope there are some performance tricks that I can do because this is just getting slower and slower.

BTW: Is there also a way to find out which server uses the most HDD r/w, because I'm new to this and can't find it.

Thanks in advance!
Tim,

[marcelo_soares]

Check if you are having high latency for the disk where this VMs are stored: http://kb.vmware.com/kb/1008205

Are all VMs stored on internal disk or you have an external storage?

[rajeshkongu]

Try to use SSD or atleast have 2 HDD like 1 TB + 1TB or you can also do raid on hardrives

[iTimOSX]

Trying the KB article now, shows wired numbers in SSH console but I gonna let it run and see what's gonna happen.

I can't use a SSD or 2 1TB HDD because it's an OVH Dedicated server.

[rajeshkongu]

Hi then try the following to get more performance,

1)If the the VM are thin provisioned then change it to thick using data store browser. This will reduce disk i/o

2) remove any snapshots or commit it

3)Run disk defragment on the vm's

4) Edit the virtual machine settings to reduce I/O usage by using more host memory

Adding the following settings to a virtual machine can reduce the I/O load on the hard disk, however these adjustments require additional memory on the host. Only add these settings if there is sufficient free memory on the host to accommodate all the memory allocated to the virtual machine, otherwise you may cause a memory starvation condition that can reduce performance of all the running virtual machines or possibly affect the host operating system. Use these settings with caution.

Open the .vmx file for the affected virtual machine while it is powered off. Add the following lines to the file using a text editor.

Note: If you are using VMware Server, you may need to restart the VMware Authorization Service (vmware-authd) for changes to take effect.

MemTrimRate = "0"
mainMem.useNamedFile= "FALSE"
sched.mem.pshare.enable = "FALSE"
prefvmx.useRecommendedLockedMemSize = "TRUE"

If you find the above information usefull . Mark it as correct or usefull.

[chriswahl]

20 active VMs on a single HDD is going to be painful. There's just only so much a spinning disk can do (seek times, IOPS).

[skhoury]

It's going to be painfully slow, there really isn't much of a way around it.

For 20 VMs, you just need more spindles and RAM.  Can you migrate to another host that has a RAID0 configuration?  Or maybe a shared storage system?