Building a new machine for VM's

[Destonomos]

I'm going to be on my own and graduating college soon and I am going to be persuing a CCNA. I'm going to build a home lab and instead of buying a bunch of pc's and running up my electric bill I am thinking of building one machine and running a bunch of VM's on it.

At a bare min I am going to be running Vista x64 as the OS for the PC. Then it will probably run (all at once for lab purposes) 2 vm's of XP, 1 vm of server 2003, and a vm of fedora core.

How much memory do you think I'd need in a machine to be running all these at once? I run vm's here at my internship but just 1 vm seems to cripple a pc after a long period of time with 4 gigs of ram in XP. Are we talking about me needed upwards of 16gigs and the like?

[Joe Average]

8GB and never look back. You could work with 4GB and give each VM 512MB which really is enough to get by, but the big thing is you'll need to decide what you're going to be doing with each VM. 512MB is more than enough to run XP, or 2K3, or even Fedora and get the job done, but obviously giving each VM more RAM to work with just ensures they'll run more adequately.

8GB would allow for 1 to 1.5GB for each VM (1GB is wonderful, anything more is gravy) and still keep the host x64 OS happy as well.

Only other tip: get a quad core CPU, preferably a Core 2 Quad, and run it with as much RAM as you can afford and fit into the mobo, 8GB realistically being the minimum as I just described, but 8 or more is highly recommended.

Also, use VM software that specifically supports VT-x (meaning VirtualBox or VMWare - not VirtualPC because it doesn't support that). VT-x will allow the VMs to run at nearly native speeds as though they weren't actually VMs at all.

[Destonomos]

Yeah we use VmWare at work and that is what I was going to use. It will probably just be me running each os with standard operations within each machine. Not going to need to load programs since this is for lab purposes. I just checked the prices on ram in kits up to 16 gigs and good lord screw that idea. 8 gigs will be all I can afford :P.

[Robstar]

You really don't need that much ram. We have a box at work with 20-30 vm's on it, running linux, with linux vm's and it uses a couple of GB. We use vmware, and vm's share memory.

[basementjack]

I agree with the quad/8gig recommendation.
virtual PC is good if you're running vista and just need to play around with stuff on an as needed basis.
VMware may be the best, if you can get a hold of a copy.
Windows server 2008 comes with hyperV which is pretty good and nice and quick, but it doesn't allow over-committing of ram, so 8 gigs is a must.

there is one more reason to get 8 gigs from the start - many motherboards are flaky with 4 sticks of ram, but run fine with just 2, for an extra $100 (or less) it's best to just fill the board from day one, do your 24-48 hours of memtest and be sure the ram is all good. it would suck to start out with 4 gig, then later add some and get instability and crashes..