Xen 3.3.1 live migration : unsolicited ARP

Xen 3.3.1 live migration : unsolicited ARP

[Olivier Blanc]

 I would like to understand the condition that makes the live migration
 process to generate the unsolicited ARP REPLY, as I could never get it
 to be generated !
 
Do you have any pointer to help me understand the process ?
 
Here is my network architecture  :

     LAN0                                                  LAN1
       |                                                     |
 +-----+-----------------------------------------------------+-----+
 |     |                                                     |     |
 |   eth0                                                  eth1    |
 |     |                                                     |     |
 |     +---------------+--------------------+                |     |
 |     |               |                    |                |     |
 |     |     +---------+---------+ +--------+--------+       |     |
 |     |     |                   | |                 |       |     |
 |     |     |       eth0.2      | |     eth0.3      |       |     |
 |     |     |                   | |                 |       |     |
 |     |     |    vif1.0  vif1.1 | |  vif2.0  vif2.1 |       |     |
 |     |     |    tap1.0  tap1.1 | |  tap2.0  tap2.1 |       |     |
 |     |     +------+-------+----+ +----+-------+----+       |     |
 |     |            |       |           |       |            |     |
 |     |     +------+-------+-----------+-------+------+     |     |
 |     |     |      |       |           |       |      |     |     |
 |     |     | +----+-------+----+ +----+-------+----+ |     |     |
 |     |     | |    |       |    | |    |       |    | |     |     |
 |     |     | |  eth0    eth1   | |  eth0    eth1   | |     |     |
 |     |     | |    |       |    | |    |       |    | |     |     |
 |   +-+-+   | |    |     +-+-+  | |    |     +-+-+  | |     |     |
 |   |   |   | |    |     |   |  | |    |     |   |  | |     |     |
 |  lvs ssh  | |   ssh   www j2ee| |   ssh   www j2ee| |    nfs    |
 |           | |                 | |                 | |           |
 |  Domain0  | |     Domain1     | |     Domain2     | |  Domain0  |
 +-----------+ +-----------------+ +-----------------+ +-----------+

I am working with Xen 3.3.1. Dom0 is an OpenSuse 11.1 kernel
2.6.27.21-0.1-xen

Thanks for your advices and help

Olivier

RE: Xen 3.3.1 live migration : unsolicited ARP

[James Harper]

> 
>  I would like to understand the condition that makes the live
migration
>  process to generate the unsolicited ARP REPLY, as I could never get
it
>  to be generated !
> 
> Do you have any pointer to help me understand the process ?
> 

Do you have STP enabled on your bridge? If enabled, it could delay the
bridge port coming up for long enough that the ARP packet gets lost.

James 

RE: Xen 3.3.1 live migration : unsolicited ARP

[Olivier Blanc]

> > 
> >  I would like to understand the condition that makes the live
> migration
> >  process to generate the unsolicited ARP REPLY, as I could never get
> it
> >  to be generated !
> > 
> > Do you have any pointer to help me understand the process ?
> > 
> 
> Do you have STP enabled on your bridge? If enabled, it could delay the
> bridge port coming up for long enough that the ARP packet gets lost.
> 
> James 

No STP is off in my bridge and forwardDelay is set to 0.

And the bridge port is ready very quickly, if I set the following
parameters value in the "ntable" of the bridge to 
reachable -> 12
delay_probe -> 20
ucast_probes -> 0

Then I lose only 2 ping transactions (less than 2 secs) to the migrated
DOMU. 

Olivier