[FreeNX-kNX] Load Balancing

[Florian Schmidt]

Hi,



Because I am also interested in FreeNX Load Balancing here what I now (assume) compared how it works with Citrix Metaframe:



The Client connects to the Load Balancer and depending on the Algorithm (Random, Round Robin, Load) gets forwarded to the final Server. 



If the servers share the same session DB (high available NFS share) it would be possible to connect to every Server directly and get redirected to the correct host (all machines are loadbalancer and NX server). 



The problem I saw during my tests was that the Machine making the load balancing is always a single point of failure because the session isn't redirected but goes through the loadbalancer (which costs bandwidth and performance on the loadbalancer) so when the loadbalancer goes down the connections to the nxservers go also down, till the load balancer (or an other loadbalancer with the same session DB) is available again.



Here is how this is handled in ICA (Citrix Metaframe) which is only running on Solaris and other commercial UNIX but not Linux :(



The Client connects to any of the ICA servers and the server checks if there is a session running for the user or not. If not or the user chooses to make a new session the server forwards the client to the best server available depending on the load balancing algorithm. The client starts a connection directly with the new server. So if any ICA server goes down only the sessions on this server are affected.



Please correct me if I am wrong in any point or the FreeNX can be configured for better availability (sessions doesn't go through loadbalancer).



Currently we have between 60 and 100 concurrent sessions on one server and a high need to use load balancing on further machines. I currently have a nice test environment so I can test all suggestions and write a small howto for load balancing.



Cheers

Florian



-------- Original-Nachricht --------

> Datum: Mon, 4 Aug 2008 15:59:16 -0500

> Von: "7th Sign | Iván Rico" <7th_sign at soy-geek.com>

> An: "User Support for FreeNX Server and kNX Client" <freenx-knx at kde.org>

> Betreff: [FreeNX-kNX] Load Balancing



> Hello list,

> 

> If I want to give NX sessions for about 300 users, I'm going to need more

> power than 1 Server, I'm going to need something like a cluster.

> therefore I wonder if FreeNX supports load balancing.

> 

> if so... How can I do that? are there a manual, URL or something like

> that?

> if not, what are your recomendations?

> 

> 

> 7th Sign | Iván Rico


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