[NTLUG:Discuss] VM Host Resources

[Ralph Green]

Howdy,
  Neil kind of hinted at it, but I'll flat out ask.  What kind of VMs
are you going to be running?  Are they going to run 24/7?  Do you
expect a lot of IO?  I use mostly VirtualBox and it does fine for most
of my needs.  I am using KVM more and more because of all the tools
being built around it(and I now have machines to experiment with that
have hardware virtualization support).  I have not used VMWare for a
while.  It has its uses, and I should probably get reacquainted with
it, since it has the most commercial usage.

 I have a couple of servers that run a lot(an ftp server and a
streaming audio server).  Neither one does much disk IO.  Your use
case may be different.  A lot of the VMs I use are to test Linux
distros.  I don't do heavy IO on those usually.  Someone on this list
noted that VirtualBox dynamically allocated images were slow.  I
normally use them.  On one image, for compiling embedded linux images,
I compared fixed versus variable and the fixed was much faster.

  On a Core 2 Duo with 2 gig of ram, I regularly kept 2 VMs running
all the time.  I could run 3, but it got sluggish.  Memory was almost
always my constraint.  The motherboard on that system died, and I am
testing its successor.  It has a whopping 8 gig of DDR3 ram, so I
expect to give more memory to the VMs and run 3 or 4 VMs regularly.
My new machine is an AMD A4-3400 based system.

 VirtualBox will run on just about anything.  It needs enough ram.
KVM needs hardware virtualization.  Almost all AMD chips have that.  I
have it on my AMD based netbook, but a few lowend AMD chips leave the
feature off.  A lot of Intel chips have it, but Intel left it off of a
lot of desktop oriented chips.  The used it as a differentiator to get
you to upgrade.    I setup a recent Celeron that had hardware
virtualization support.  So, Intel is getting better, but especially
if the system is not new, check the CPU if it is an Intel and you want
to run KVM.
Have fun,
Ralph