Web farm on IIS 7.5 with ASP.NET

To create web farm we use severeal IIS 7.5 servers and on e balancer server on linux.

HAProxy is very fast and flexible load balancer. It can manage SSL sessions via its TCP mode:

listen site_frontend 192.168.0.10:443
mode tcp
option tcplog
balance roundrobin
server  site_backend1 192.168.0.101:443 check weight 30

server  site_backend2 192.168.0.102:443 check weight 30

server  site_backend3 192.168.0.103:443 check weight 40

To prepare ASP.NET application on IIS server for web farm you need:

1. Use common session storage (ASPState base for sessions)

2. Syncronize IIS Machine Key between all servers. Here is the Microsoft instruction. Remeber, that you should syncronize .NET Framework machine key for both versions: 86 and x64, if you OS is 64-bit:

%windir%\Microsoft.NET\Framework64\v2.0.50727\CONFIG\web.config

%windir%\Microsoft.NET\Framework\v2.0.50727\CONFIG\web.config