Xen users - Apr 2007 - Live Migration, ARP, MAC addresses and switches

Hi,

I have an annoying situation with my network switches (HP 5024) and the
DomU live migration.

When the DomU moves between servers, all network traffic stops until some
packets are sent from the DomU. The problem is that the DomU MAC address
and switch port association is not updated until the DomU generates a
frame, and the switch learn the new MAC location.

I though that the migration process includes the use of gratuitous ARP to
face this situation and update the MAC address table of the switches.
Reading the list archives I have found some messages talking about this
unsolicited ARP, but in my Debian Xen server (3.0.3-1) it doesn''t work
in
this way.

Some information about this?

Thanks.




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this was broken for a while (in 3.0.3 I think) and then fixed in Unstable by
Keir around a month ago; the ARP messages were being dropped by the bridge in
Dom0. See
http://lists.xensource.com/archives/html/xen-devel/2007-03/msg00111.html for
more info.
 
Simon

________________________________

From: xen-users-bounces@lists.xensource.com on behalf of Angel Lopez
Sent: Wed 18/04/2007 8:21 AM
To: xen-users@lists.xensource.com
Subject: [Xen-users] Live Migration, ARP, MAC addresses and switches



Hi,

I have an annoying situation with my network switches (HP 5024) and the
DomU live migration.

When the DomU moves between servers, all network traffic stops until some
packets are sent from the DomU. The problem is that the DomU MAC address
and switch port association is not updated until the DomU generates a
frame, and the switch learn the new MAC location.

I though that the migration process includes the use of gratuitous ARP to
face this situation and update the MAC address table of the switches.
Reading the list archives I have found some messages talking about this
unsolicited ARP, but in my Debian Xen server (3.0.3-1) it doesn''t work
in
this way.

Some information about this?

Thanks.




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Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users




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> this was broken for a while (in 3.0.3 I think) and then fixed in Unstable
> by Keir around a month ago; the ARP messages were being dropped by the
Thanks. So is it fixed in recent xen patches for the 2.6 kernel or have I
to install a complete newer Xen distribution?

Un saludote.

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> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> Angel Lopez
> Sent: 18 April 2007 15:05
> To: Graham, Simon
> Cc: xen-users@lists.xensource.com
> Subject: RE: [Xen-users] Live Migration, ARP, MAC addresses 
> and switches
> 
> 
> > this was broken for a while (in 3.0.3 I think) and then 
> fixed in Unstable
> > by Keir around a month ago; the ARP messages were being 
> dropped by the
> 
> Thanks. So is it fixed in recent xen patches for the 2.6 
> kernel or have I
> to install a complete newer Xen distribution?
I would expect the patch to apply relatively nicely to any old xenified
Linux:
http://xenbits.xensource.com/xen-unstable.hg?rev/42b29f084c31

--
Mats
> 
> Un saludote.
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 
> 
> 


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Hi,
> I would expect the patch to apply relatively nicely to any old xenified
> Linux:
> http://xenbits.xensource.com/xen-unstable.hg?rev/42b29f084c31
If I build all from the latest version in the Mercurial repository
(http://xenbits.xensource.com/xen-3.0.4-testing.hg) would be OK?


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> -----Original Message-----
> From: Angel Lopez [mailto:angel@futur3.com] 
> Sent: 18 April 2007 19:59
> To: Petersson, Mats
> Cc: Graham, Simon; xen-users@lists.xensource.com
> Subject: RE: [Xen-users] Live Migration, ARP, MAC addresses 
> and switches
> 
> Hi,
> 
> > I would expect the patch to apply relatively nicely to any 
> old xenified
> > Linux:
> > http://xenbits.xensource.com/xen-unstable.hg?rev/42b29f084c31
> 
> If I build all from the latest version in the Mercurial repository
> (http://xenbits.xensource.com/xen-3.0.4-testing.hg) would be OK?
Don''t believe so [it would have to have been back-ported, and none of
the patches after the 3.0.4 release contains this, and the patch linked
above is WAY later than 3.0.4 release (changeset 13099 in the 3.0.4
tree, that''s not the same as 13099 in unstable, but close). Do you want
me to mail you the patch as a text-attachment?

Looking a bit further at it: The patch I linked above is from
07-March-2007, the latest patch in 3.0.4-testing is 15-Feb-07. So the
answer is definitely NO, it''s not in 3.0.4-testing. 

You can either build unstable, or patch the above patch into any build
you''d like (3.0.4-testing isn''t a bad choice until 3.0.5 comes
out).

--
Mats
> 
> 
> 
> 


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Hi Mats,

I don''t know how "unstable" is the xen-unstable distribution
for been
installed in a production server. Maybe is safer to apply the patch in the
3.0.4 distribution.

Thanks a lot for your help.
>> -----Original Message-----
>> From: Angel Lopez [mailto:angel@futur3.com]
>> Sent: 18 April 2007 19:59
>> To: Petersson, Mats
>> Cc: Graham, Simon; xen-users@lists.xensource.com
>> Subject: RE: [Xen-users] Live Migration, ARP, MAC addresses
>> and switches
>>
>> Hi,
>>
>> > I would expect the patch to apply relatively nicely to any
>> old xenified
>> > Linux:
>> > http://xenbits.xensource.com/xen-unstable.hg?rev/42b29f084c31
>>
>> If I build all from the latest version in the Mercurial repository
>> (http://xenbits.xensource.com/xen-3.0.4-testing.hg) would be OK?
>
> Don''t believe so [it would have to have been back-ported, and none
of
> the patches after the 3.0.4 release contains this, and the patch linked
> above is WAY later than 3.0.4 release (changeset 13099 in the 3.0.4
> tree, that''s not the same as 13099 in unstable, but close). Do you
want
> me to mail you the patch as a text-attachment?
>
> Looking a bit further at it: The patch I linked above is from
> 07-March-2007, the latest patch in 3.0.4-testing is 15-Feb-07. So the
> answer is definitely NO, it''s not in 3.0.4-testing.
>
> You can either build unstable, or patch the above patch into any build
> you''d like (3.0.4-testing isn''t a bad choice until 3.0.5
comes out).
>
> --
> Mats
>>
>>
>>
>>
>
>
>

Un saludote.

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> -----Original Message-----
> From: Angel Lopez [mailto:angel@futur3.com] 
> Sent: 19 April 2007 11:55
> To: Petersson, Mats
> Cc: Graham, Simon; xen-users@lists.xensource.com
> Subject: RE: [Xen-users] Live Migration, ARP, MAC addresses 
> and switches
> 
> Hi Mats,
> 
> I don''t know how "unstable" is the xen-unstable
distribution for been
> installed in a production server. Maybe is safer to apply the 
> patch in the
> 3.0.4 distribution.
The stability (or lack thereof) depends very much on which day you grab
the unstable - it is, after all, the development version of Xen, so
it''s
changing, usually many times per day. At the moment, it is generally
stable, but HVM Save/Restore that I work with have been working one day,
not the next, then working again, and so on. 

For the "common functions", it''s generally working. 

But 3.0.4-1 is a much more well-known entity, so I suggest that''s a
more
safe choice.

Are you able to grab the patch, or do you want me to mail it to you?

--
Mats
> 
> Thanks a lot for your help.
> 
> >> -----Original Message-----
> >> From: Angel Lopez [mailto:angel@futur3.com]
> >> Sent: 18 April 2007 19:59
> >> To: Petersson, Mats
> >> Cc: Graham, Simon; xen-users@lists.xensource.com
> >> Subject: RE: [Xen-users] Live Migration, ARP, MAC addresses
> >> and switches
> >>
> >> Hi,
> >>
> >> > I would expect the patch to apply relatively nicely to any
> >> old xenified
> >> > Linux:
> >> > http://xenbits.xensource.com/xen-unstable.hg?rev/42b29f084c31
> >>
> >> If I build all from the latest version in the Mercurial repository
> >> (http://xenbits.xensource.com/xen-3.0.4-testing.hg) would be OK?
> >
> > Don''t believe so [it would have to have been back-ported, 
> and none of
> > the patches after the 3.0.4 release contains this, and the 
> patch linked
> > above is WAY later than 3.0.4 release (changeset 13099 in the 3.0.4
> > tree, that''s not the same as 13099 in unstable, but close). 
> Do you want
> > me to mail you the patch as a text-attachment?
> >
> > Looking a bit further at it: The patch I linked above is from
> > 07-March-2007, the latest patch in 3.0.4-testing is 
> 15-Feb-07. So the
> > answer is definitely NO, it''s not in 3.0.4-testing.
> >
> > You can either build unstable, or patch the above patch 
> into any build
> > you''d like (3.0.4-testing isn''t a bad choice until
3.0.5 comes out).
> >
> > --
> > Mats
> >>
> >>
> >>
> >>
> >
> >
> >
> 
> 
> Un saludote.
> 
> 
> 


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Hi Mats,
> For the "common functions", it''s generally working.
Cool, I''ll try the unstable in a test server.
> But 3.0.4-1 is a much more well-known entity, so I suggest that''s
a more
> safe choice.
>
> Are you able to grab the patch, or do you want me to mail it to you?
Don''t you mind to send me the patch by E-Mail? I''ll try to
apply it to 3.0.4

Thanks a lot.

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