Memory overcommit

[Tracy R Reed <treed@copilotconsulting.com>]

I have been using Xen on a daily basis on a production (but not
critical) machine for a number of months now. It's looking really good.

One thing that I have not yet seen anyone mention as a feature that I
would really like to see is the ability to overcommit memory. I have 2G
of RAM in my machine. I would like to give a developer his own virtual
domain to sandbox his application development without having to dedicate
a whole piece of hardware to just him. But I know he won't really log in
and use it all that often. If I give him 512M of my 2G that's 25% of my
memory that will likely be unutilized most of the time. It would be
great if I could assign more memory to domains than I actually have and
just let it swap out idle pages. I bet there are a lot of boxes out
there, especially in webserver colo's, that really don't get much
traffic and really don't need as much RAM as they have in them for
normal day to day operations. Just let them swap everything back in and
use up to the maximum RAM configured for that domain if they get busy
and need it but let it swap out the rest of the time so other busier
domains can use the physical RAM.

This is feature #1 on my Xen wishlist. Is there any work going into this
area?

-- 
Tracy R Reed
http://copilotconsulting.com
1-877-MY-COPILOT