[dundee] VMWare Server 2.0

[gordon dunlop]

2008/10/2 Lee Hughes <toxicnaan at yahoo.co.uk>:
>
> Thing that gets me about virtual machines is memory usage, it all well and
> good on
> a single machine (non vm)  you can have say 1GB of ram and setup 2GB of swap
> space,
> but linux seems rather lazy about claiming and reclaiming memory, if I look
> at my own
> machine I have 1GB of ram,  and currently using 787MB of swap! This would
> cause
> havoc in a virtual environment.... okay I need a memory upgrade.
>
> Until linux applications constrain their memory use , or they can be given
> hints on
> maximum or minimum  memory use then using any virtual machine technology
> that
> support paging to disk, is a no no.
>
> paging to disk is not usually a bit problem, as only one machine is
> effected, and that
> machine has already exhausted it's memory  , so a slow down is expected.
> Misbehaving
> VM's that are paging will effect performance of all vm's on that system.
>

VM's do have certain controls for preventing misbehaving and runaway
processes. Anyway I am going to be lazy here and just give you the
necessary papers:

This is about misbehaving machines.

Deshane, T. et al. 2006. Performance isolation of a misbehaving
virtual machine with Xen, Vmware and Solaris containers. Submitted to
USENIX06, Boston, MASS, USA.

This is a comparison between Xen & private virtual servers.

Soltesz, S. et al. 2006. Virtual doppelganger: On the performance,
isolation, and scalability of para- and paene- virtualized systems.
Submitted to Eurosys'06: European Systems Conference, Leuven, Belgium,
April 2006.

Just put some keywords from the title into Google Scholar and they
will come up in your search list. They are both downloadable PDF's,
happy reading.

Gordon