Open Stack

with gre a full-mesh architecture is created. A lot of GRE interfaces
are created, and i don't know how many interfaces are supported in
OVS.

this web page summarize scalability issue for cloudstack, but with ovs
and GRE  (in openstack, it's a single Mesh architecture):

https://cwiki.apache.org/CLOUDSTACK/enhancements-to-gre-based-sdn-overlay.html

Moreover, a GRE doesn't use NIC offloading, it is very CPU consuming,
it could be a possible issue at scale, with VM which flood the network
:

http://networkheresy.com/2012/06/08/the-overhead-of-software-tunneling/

With folsom, only one l3-agent is supported, which will do the SNAT
and floating-ips. With a lot of VM accessing external network and a
lot of floating-ips, this l3-agent could get down, but I don't know
when

On Thu, Jan 24, 2013 at 12:47 PM, Vivek Singh Raghuwanshi
<vivekraghuwanshi at gmail.com> wrote:
> Hi Rohon,
>
> i am running my openstack cloud with openvswitch with gre, can you clear
> which information you want i am using 172.24.x.x and floating ips in the
> ranve of 10.10.x.x
>
> On Thu, Jan 24, 2013 at 4:03 PM, Rohon Mathieu <mathieu.rohon at gmail.com>
> wrote:
>>
>> I was wondering if someone has an experience to share about the
>> scalability of the OVS/GRE solution.
>>
>> How many GRE tunnel are supported?
>> How many connections throught l3-agent? How many floating-IP?
>>
>> Thanks
>>
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>
>
>
>
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