Subject: Re: [RFC PATCH net-next v2 0/5] netns: allow to identify peer netns

From: David Ahern <[email-masked]>
Date: Fri, 26 Sep 2014 13:15:10 -0600

On 9/26/14, 7:40 AM, Nicolas Dichtel wrote:
>>
>>
>> No, I don't want to monitor anything. Even if I wanted, I would just
>> start one
>> daemon in each netns instead of one for all.
> Ok you don't want, but some other people (not only me) want it! And
> having one
> daemon per netns does not scale: there are scenarii with thousand netns
> which
> are dynamically created and deleted.

An example of the scaling problem using quagga (old but still seems to 
be a relevant data point):

https://lists.quagga.net/pipermail/quagga-users/2010-February/011351.html

"2k VRFs that would be 2.6G"

And that does not include the overhead of each namespace -- roughly 
200kB/namespace on one kernel I checked (v3.10). So that's a ballpark of 
3G of memory.

David