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Re: [Xen-users] Swap space for DomU

To: Stefan de Konink <skinkie@xxxxxxxxx>
Subject: Re: [Xen-users] Swap space for DomU
From: Luciano Rocha <strange@xxxxxxxxxxxxx>
Date: Fri, 28 Dec 2007 14:47:49 +0000
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On Fri, Dec 28, 2007 at 03:43:37PM +0100, Stefan de Konink wrote:
>  Luciano Rocha schreef:
> > On Fri, Dec 28, 2007 at 08:44:11AM -0500, Matthew Crocker wrote:
> >>  Should I create a file on Dom0 and assign it for a DomU for use as swap  
> >> space or should I just overcommit my system RAM and have Dom0 handle all 
> >> of  the swap?
> > There is no memory overcommit in Xen.
>  There is in Linux.

Eh? Linux runs under Xen, not the other way around. There is no sharing
of memory between virtual machines under Xen. And no usage of any swap

How the virtual machines do their memory management, is up to them.

> And if you don't believe it :) Try to do Bonnie++ in 
>  DomU, twice the amount of memory as Dom0, disable Swap on Dom0. And 'host' 
>  the filesystem on NFS. Fun for everyone!

I know Linux has overcommit, but that example seems to be a case of
cache thrashing.


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