[Openstack-operators] [Quantum] scalability

Benoit ben42ml at gmail.com
Thu Jan 24 23:10:11 UTC 2013


Hello,

Don't be scared about the scalability of  openvswitch, we use it since 
about 2 years  with central network "gre-switch" (not in openstack but 
with a good load of  hypervisor/VMs)

Only one thing, for us, was the hardcoded size of the mac table ...  
well we have modified a line in the source code, and it's ok :)

Gre tunnel is CPU consuming for network switch with limited cpu but for 
a modern x86 cpu really don't care (and i speak for a 10Gbps network).


One thing about openstack vswitch agent : I have'nt see the ability to 
specify the MTU for the gre Tunnel ?



Regards,


Le 24/01/2013 16:27, Rohon Mathieu a écrit :
> 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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