Re: scalability question

On Mar 17, 2006, at 9:31 AM, Rory I. Sinclair wrote:

> Hi there,
>
>     I'm currently working on a project involving potentially tens  
> of thousands of hosts (typically 15,000 - 20,000, but a realistic  
> maximum would be say 50,000), each advertising a small number of  
> services.  99% of the hosts will be 'clients' (conceptually) to a  
> series of network services available on a handful of 'important'  
> hosts.  They advertise services only for updates to the client  
> software, and for maintenance (go offline, go online etc).
>
> My question is about the scalability of Bonjour or Avahi or any  
> other zeroconf/mDNS/DNS-SD implementation and its suitability for  
> the following:
>
> 1) Presence awareness of the client machines - ie the 'important'  
> server hosts will use DNS-SD browse to be notified of any client  
> machines dying.
> 2) To allow the client machines to lookup network services by name  
> and resolve the host/port information at runtime, rather than  
> maintaining lookup tables
> 3) To allow clients to handle failures in the 'server' machines (eg  
> multiple instances of the network services will provide failover)
>
> Does anyone have any thoughts as to the wisdom of using Zeroconf in  
> this way?  Is it beyond the scope of it to be used for such a large  
> network?

mDNS was designed for small networks of around 1000 clients maximum.   
I doubt it would scale to 50,000 clients, given that all those  
clients would need to be on the same subnet (logical link).  But if  
you were to put 50,000 clients on a single subnet, you would have  
other performance issues to worry about regardless of mDNS.

-Marc



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