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RE: [Xen-users] streaming server on a virtual machine.

To: "Mauro" <mrsanna1@xxxxxxxxx>
Subject: RE: [Xen-users] streaming server on a virtual machine.
From: Jeff Sturm <jeff.sturm@xxxxxxxxxx>
Date: Fri, 18 Sep 2009 09:27:33 -0400
Cc: xen-users <xen-users@xxxxxxxxxxxxxxxxxxx>
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Thread-topic: [Xen-users] streaming server on a virtual machine.
> -----Original Message-----
> From: Mauro [mailto:mrsanna1@xxxxxxxxx]
> Sent: Friday, September 18, 2009 6:52 AM
> To: Jeff Sturm
> Cc: xen-users
> Subject: Re: [Xen-users] streaming server on a virtual machine.
> 2009/9/18 Jeff Sturm <jeff.sturm@xxxxxxxxxx>:
> > I don't see why not.  If you're concerned about latency you could always
> > pin the server to a physical CPU.
> I'm thinking about the limitation of the NIC.

I've pushed xennet close to wire speeds from a domU.  The paravirt drivers do 
not seem to present much of a bottleneck.

I'd encourage anyone asking similar questions to try it for themselves... I 
did, and learned a lot about Xen by pushing it to its limits.

One thing to note however.  Xen's network layer may not cope well with a 
substantial number (10-20) of virtual hosts performing high rates of concurrent 
network I/O.  I do not know if this is a limitation of the net back driver, 
Linux bridging or something else...I spotted it early on when I had each domU 
mounting filesystems from a networked SAN.  Switching the SAN traffic over to 
dom0 and exporting block devices to each domU made a world of difference, and 
allowed us to use CLVM to easily manage the storage as well.

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