WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

Re: [Xen-users] New user question...

> > -- In the VWware ESX server product, identical memory pages among
> > similar domains can be transparently consolidated to free up more
> > physical RAM for the domains to use.  Is this also the case in Xen?
>
> I'm not sure, but AFAIK it is not. Xen is designed with hosting
> companies in mind. They want to charge users for the amount of memory
> (etc.) they use, and sharing the memory like that would make that much
> harder. It would also cause problems when domains wish to make changes
> to transparently shared pages if there is not enough free memory to copy
> them apart.

The Xen philosophy is to expose the real resources to domains, where possible.  
So you just allocate memory to a domain and say "This is how much RAM you 
have, please do all your own swapping".  For greater flexibility you can also 
change domain memory allocations at runtime as the workloads in the domains 
change.

A number of people are looking at new ways to implement sharing on Xen: one 
group is trying to run thousands of virtual machines on one system (by 
sharing *loads* of memory!), meanwhile with XenFS I'm trying to share the 
memory taken up by disk IO.

Cheers,
Mark

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users