Web garden in IIS

What are web gardens?

Web gardens are different from Web farms. A Web garden is configured on a single server by specifying multiple worker processes for an application pool. Web farms use multiple servers for a Web site.

Creating a Web garden for an application pool can also enhance performance in the following situations:

• ·         Robust processing of requests: When a worker process in an application pool is tied up (for example, when a script engine stops responding), other worker processes can accept and process requests for the application pool.
• ·         Reduced contention for resources: When a Web garden reaches a steady state, each new TCP/IP connection is assigned, according to a round-robin scheme, to a worker process in the Web garden. This helps smooth out workloads and reduce contention for resources that are bound to a worker process.

When do we need to go for a Web garden?

More RAM:

If you have a single process serving a site/application and compare it to a web garden of five processes serving the exact same traffic load, you'll generally see more RAM consumed on the server. Part of the reason is because just spinning up a .NET application, even with no load, requires a certain amount of memory overhead. Another reason could be related to any application caching – multiple copies of the cached data (one per process) needs to be stored.

More CPU:

Multiple processes often consume more processor capacity in a web garden even with consistent traffic loads. In general, the more processes that an OS has to track and manage, the more resources it takes. I'm not sure exactly why, but we've seen processor usage climb drastically as web garden process counts are increased. On a busy web server it can actually overload the server, where the same load in a single process might handle all requests perfectly with a much lower overall resource load.