Re: FreeBSD HVM guests?

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

Hugo Silva wrote:
> Manuel Bouyer wrote:
>> On Mon, May 11, 2009 at 04:40:55PM -0400, Steven M. Bellovin wrote:
>>  
>>> On Mon, 11 May 2009 16:15:46 +0200
>>> Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:
>>>
>>>    
>>>> On Mon, May 11, 2009 at 02:50:11PM +0100, Hugo Silva wrote:
>>>>      
>>>>> Hi,
>>>>>
>>>>> I am considering to install NetBSD 5/Xen (64 bits) on some servers
>>>>> that currently run FreeBSD 7/amd64. I've been testing NetBSD/Xen
>>>>> i386 on older hardware (no hardware virtualization support) with
>>>>> NetBSD PV domU's; It seems to work just fine.
>>>>>
>>>>> For my purposes, however, I need FreeBSD guests, and I am unable to
>>>>> test this at the moment.
>>>>>
>>>>> I would like to know if anyone has useful feedback regarding HVM
>>>>> guests, FreeBSD in particular, and NetBSD/Xen dom0 stability and
>>>>> maturity in general.
>>>>>         
>>>> NetBSD/Xen dom0 is stability is good; I've several servers running it,
>>>> with NetBSD PV, linux PV, linux HVM and windows HVM guests. No
>>>> problems so far.
>>>>
>>>> I would expect a FreeBSD HVM guest to run just fine; it will see a
>>>> PIIX3 IDE controller and a ne2000 ethernet device. Be aware that
>>>> I/O performances won't be great using these emulated device though;
>>>> but if your FreeBSD guest doesn't do mych I/O it should be fine.
>>>>
>>>>       
>>> I thought FreeBSD had domU support at this point.  If I'm right,
>>> wouldn't that help I/O performance a lot?
>>>     
>>
>> it would, yes. if there is a FreeBSD PV kernel it would be the
>> best option
>>
>>   
> 
> It does have domU support, altough with some problems -
> http://wiki.freebsd.org/FreeBSD/Xen
> 
> The servers I have in mind are fairly busy webservers, quad core CPUs,
> so much for low I/O.
> 
> In your experience, is the slowdown due to HVM unnaceptable? Out of
> curiosity, could the ne2000 emulated device saturate even a 100mbit link
> (I'm running on gigabit) ?
> 
> Too many questions and not enough hardware here.. :-)

Append

, model=e1000

in the vif line to get an emulated Intel e1000 device.
This chip features highlevel commands whichs makes its emulation
cheaper from performance point of view.

Christoph