How many simultaneous VMs could I run on a MBP w/8GB of RAM and still have good performance?

Question

I'm considering buying a new MBP w/8GB of ram (dual core 3GHz). I would like to run at least 3 VMs simultaneously (using vmware fusion 3 running W7, arch linux, other) plus snow leopard apps. What kind of performance can I expect?

Would performance be meaningfully better/worse if I used W7 rather than snow leopard as the host OS?

Appreciate the help!

Answer 1

Performance is really hard to judge without knowing a lot more.

Modern computers are so fast, the real limitation of virtualisation at the moment comes from hard drive I/O.

I have a T9300 CPU and 4GB's of memory, I can run about 8 - 10 VMs when I do cluster testing with Linux where each VM hardly uses any I/O and I can run them without any sort of slow downs, where as when I am doing benchmarking or similar reviewing, it can instantly slow down the entire machine from just having one VM open.

So, it depends what you are planning on doing... Personally, for every day usage, you shouldn't have a problem as your specification seems higher than what I use, and I am able to do what you want.

Answer 2

Since it sounds like you are going to be using VMware Fusion for desktop virtualization you should be able to get near native performance (at least perceivably for desktop applications). For comparison, I can comfortably run Win7 apps using fusion on my 2 year old macbook that has 2gb of RAM.

I don't think that running Win7 using bootcamp instead of Snow Leopard would be worth it unless you regularly use demanding windows apps (e.g. 3d games).

Answer 3

I have a VMware server running on a Linux system with 8G memory, and it happily hosts about a dozen virtual machines, mostly Linux, but a 1G OpenSolaris VM and a 2G Windows 7 VM as two of the biggest resource usage.

I think you'll be fine with a MBP running OS X and VMware Fusion, assuming:

• ~2G for Windows 7.
• ~1G for Arch Linux.
• ~1G? for Other?

Hard to say for sure about 'other' but 1G should run most operating systems just fine in a VM. The rest of the memory, ~4G will be sufficient for Snow Leopard and your regular desktop applications.

Answer 4

What does your disk subsystem look like? In my experience this is one of the major limiting factors. For three concurrently running virtual machines, I would highly recommend RAID 5 or RAID 10. If that's the case, with two cores, you can expect decent performance. Obviously all three VMs can't be at 100% CPU usage at once, but all three can be at 50-85% usage at once.

Answer 5

0, You can run 0 VMs without any impact on performance. After that 1, 2 or more VMs affect performance.