From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: How much memory does a domain REALLY use...
Date: Mon, 26 Feb 2007 13:27:41 +0000
Message-ID: <C20890CD.A206%keir@xensource.com>
References: <20070226124142.4119914C02B@irishsea.home.craig-wood.com>
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On 26/2/07 12:41, "Nick Craig-Wood" <nick@craig-wood.com> wrote:

>>  Yes, there's an overhead of 7MB per 1GB on i386, and 12MB per 1GB
>>  on x86/64.
> 
> Some time ago (xen 3.0.2 I think) I measured the overhead on i386 to be
> 
>   12 MB per domain

Do you mean 12MB static overhead for Xen itself? There is no 12MB overhead
per guest, unless you are talking about HVM guests in which case there is
some shadow-pagetable overhead (I'm not sure it's as much as 12MB though).

 --Keir

>   plus 6MB per GB host RAM
> 
> I guess it has gone up since the above figures fit the 7MB amount much
> better
> 
>>>> for total in (2, 6, 8, 16): print "Total",total,"Calculated
>>>> used",total*7+12+768
> ... 
> Total 2 Calculated used 794
> Total 6 Calculated used 822
> Total 8 Calculated used 836
> Total 16 Calculated used 892