VMWare questions (memory overcommit)

[Rich Braun]

After seeing this discussion about VMware's memory-overcommit feature, I got
curious as to whether VirtualBox has anything like it.

It does, and the term they use to describe it is "memory ballooning" which can
be accessed via the CLI command "VBoxManage controlvm foo guestmemoryballoon
NNN".

I haven't tried it yet (so far I've been able to just go out and buy more RAM,
but I'm maxed out now so next expansion will prod me to test the limits).  THe
main limitations of this seem to be that (a) it's not quite as automatic as
the VMware mechanism and (b) the host O/S doesn't get to use the overcommitted
memory.  The latter is no big deal:  my host O/S is basically just a glorified
ESXi-like installation with a few extra software packages that allow me to run
a caching named, filesystem backups, and such.

A brief description of VIrtualBox memory ballooning is in the Guest Additions
section of the VirtualBox manual: 
http://www.virtualbox.org/manual/ch04.html#guestadd-balloon

-rich