Xen users - Dec 2006 - Setting up a "dumb" network for domU''s

Hi all,

 Under VMWare server (and Workstation) I can use a vmnet interface (like
vmnet4, vmnet5, etc ...) that it is not connected to any physical device on
host, and then use it as a virtual network with 100Mbps throughput (more or
less). How can I do this with xen 3.0.3??? Using dummy kernel''s module?
I
have tried with it, but throughput it is very very bad (only 2 Mbps).

Many thanks.


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Hello,

Have a look at XenNetworking :
http://wiki.xensource.com/xenwiki/XenNetworking

For every VM xen creates vif<domain_id>.<interface_number> on Dom0 ,
you
can make a bridge with your vif''s interfaces without adding your eth0
(the real one) to it .. so you have a private networking between your
VMs.

If you want to add your Dom0 to the thing, have a loop in the netloop
kernel module (loaded by xend by default). It will create a veth0 <->
vif0.0 / veth1 <-> vif0.1 <and so on> pairs, so you can add vif0.0
to
the bridge earlier mentioned and use veth0 in your Dom0.

It takes a while to understand how the whole thing works, but still it
worth ;)

[]''s

Theo

On Wed, 2006-12-06 at 00:28 +0100, C. L. Martinez wrote:
> Hi all,
> 
>  Under VMWare server (and Workstation) I can use a vmnet interface
> (like vmnet4, vmnet5, etc ...) that it is not connected to any
> physical device on host, and then use it as a virtual network with
> 100Mbps throughput (more or less). How can I do this with xen 3.0.3???
> Using dummy kernel''s module? I have tried with it, but throughput
it
> is very very bad (only 2 Mbps).
> 
> Many thanks.
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users

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On 6 Dec 2006 at 12:00, Theo Cabrerizo Diem wrote:
> Have a look at XenNetworking :
> http://wiki.xensource.com/xenwiki/XenNetworking
> 
The remaining question is: Why are there only three bridged supported in XEN
(docs
say so). Where is that limit, and can it be raised?

I''m wondering whether I should move bonding from Dom0 to DomUs, but
then I''d need
four bridges at least...

Regards,
Ulrich


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> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> Ulrich Windl
> Sent: 06 December 2006 11:36
> To: xen-users@lists.xensource.com
> Subject: Re: [Xen-users] Setting up a "dumb" network for
domU''s
> 
> On 6 Dec 2006 at 12:00, Theo Cabrerizo Diem wrote:
> 
> > Have a look at XenNetworking :
> > http://wiki.xensource.com/xenwiki/XenNetworking
> > 
> 
> The remaining question is: Why are there only three bridged 
> supported in XEN (docs 
> say so). Where is that limit, and can it be raised?
Because each page (4K) can hold 3 x 1536 bytes of network packets -
which means that the buffer(s) for the network devices can all be fitted
into a single page. 

It can be raised, but it''s non-trivial, as far as I understand it. 

--
Mats
> 
> I''m wondering whether I should move bonding from Dom0 to 
> DomUs, but then I''d need 
> four bridges at least...
> 
> Regards,
> Ulrich
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 
> 
> 


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Still on this topic :

Is there any network speed limit between the Dom0 and DomU''s ?

Example, in this user''s scenario, can''t him make the bonding
on the Dom0
and add the "trunk" interface in the bridge with the DomUs ?

IMHO this would work unless there''s a speed limit in the network level,
let''s say 100 Mbit/s between a domU eth0 and Dom0 vif equivalent.

Still .. if he doesn''t need 4xinterfaces bonding for each domU, (but
for
the sum of DomUs, let''s say for a SAN), he can still do the bonding on
Dom0 and have a <limited> interface per DomU, which isn''t that
bad.

[]''s

Theo


On Wed, 2006-12-06 at 12:47 +0100, Petersson, Mats
wrote:
>  
> > -----Original Message-----
> > From: xen-users-bounces@lists.xensource.com 
> > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> > Ulrich Windl
> > Sent: 06 December 2006 11:36
> > To: xen-users@lists.xensource.com
> > Subject: Re: [Xen-users] Setting up a "dumb" network for
domU''s
> > 
> > On 6 Dec 2006 at 12:00, Theo Cabrerizo Diem wrote:
> > 
> > > Have a look at XenNetworking :
> > > http://wiki.xensource.com/xenwiki/XenNetworking
> > > 
> > 
> > The remaining question is: Why are there only three bridged 
> > supported in XEN (docs 
> > say so). Where is that limit, and can it be raised?
> 
> Because each page (4K) can hold 3 x 1536 bytes of network packets -
> which means that the buffer(s) for the network devices can all be fitted
> into a single page. 
> 
> It can be raised, but it''s non-trivial, as far as I understand it.
> 
> --
> Mats
> > 
> > I''m wondering whether I should move bonding from Dom0 to 
> > DomUs, but then I''d need 
> > four bridges at least...
> > 
> > Regards,
> > Ulrich
> > 
> > 
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
> > 
> > 
> > 
> 
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 

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On 6 Dec 2006 at 12:47, Petersson, Mats wrote:
> > The remaining question is: Why are there only three bridged 
> > supported in XEN (docs 
> > say so). Where is that limit, and can it be raised?
> 
> Because each page (4K) can hold 3 x 1536 bytes of network packets -
> which means that the buffer(s) for the network devices can all be fitted
> into a single page. 
Ah, that explains why there are not virtual jumbo frames ;-)
Still I wonder why different bridged must share a page. Traffic should be quite 
idependent on each bridge.
> 
> It can be raised, but it''s non-trivial, as far as I understand it.
Regards,
Ulrich


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