added a comment about balancing and documented the

new proxy.balance option


git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.3.x@385 152afb58-edef-0310-8abb-c4023f1b3aa9

doc/proxy.txt

@@ -35,6 +35,16 @@ lighttpd provides the Proxy support via the proxy-module
   Proxy module. Currently only 0 and 1 are used. Use 1 to 
   enable some debug output, 0 to disable it.
 
+:proxy.balance:
+  might be one of 'hash', 'round-robin' or 'fair' (default).
+  
+  'round-robin' choses another host for each request, 'hash'
+  is generating a hash over the request-uri and makes sure
+  that the same request URI is sent to always the same host.
+  That can increase the performance of the backend servers
+  a lot due to higher cache-locality. 'fair' is the normal
+  load-based, passive balancing.
+
 :proxy.server:
   tell the module where to send Proxy requests to. Every 
   file-extension can have its own handler. Load-Balancing is 
@@ -43,30 +53,52 @@ lighttpd provides the Proxy support via the proxy-module
   structure of proxy.server section: ::
   
     ( <extension> => 
-      ( <handle> => 
+      ( 
         ( "host" => <string> ,
-          "port" => <integer>
-	)
-      ), 
-      ( <handle> => ... 
-      )
+          "port" => <integer> ),
+        ( "host" => <string> ,
+          "port" => <integer> )
+      ),
+      <extension> => ... 
     )
   
-  :<extension>: is the file-extension or prefix 
-                (if started with "/")
-  :<handle>:    is just a unique handle name
+  :<extension>: is the file-extension or prefix (if started with "/")
+                might empty to match all requests
   :"host":      is ip of the proxy server
   :"port":      is tcp-port on the "host" used by the proxy
-                server
+                server (default: 80)
 
   e.g.: ::
   
-    proxy.server = ( ".php" =>
-  		       ( "grisu" => 
-		         ( 
-		           "host" => "192.168.0.2",
-		           "port" => 1026
-		         )
-		       )
+    proxy.server = ( ".jsp" =>
+  		       ( ( 
+		           "host" => "10.0.0.242",
+		           "port" => 81
+		         ) )
 		     )
 
+Example:
+========
+
+Using lighttpd + mod_proxy in front of 8 Squids which handle the 
+caching of dynamic content for you. All requests for the host 
+www.example.org should be forwarded to the proxy. All proxies
+listen on port 80 for requests. ::
+
+  $HTTP["host"] == "www.example.org" {
+    proxy.balance = "hash"
+    proxy.balance = ( "" => ( ( "host" => "10.0.0.10" ),
+                              ( "host" => "10.0.0.11" ),
+                              ( "host" => "10.0.0.12" ),
+                              ( "host" => "10.0.0.13" ),
+                              ( "host" => "10.0.0.14" ),
+                              ( "host" => "10.0.0.15" ),
+                              ( "host" => "10.0.0.16" ),
+                              ( "host" => "10.0.0.17" ) ) )
+  }
+
+If one of the hosts goes down the all requests for this one server are 
+moved equally to the other servers. If you want to know more about
+the algorithm used here google for 'Microsoft CARP'.
+
+