Types of session management

Session object is used to store state specific information per user basis.Session object can be configured 3 ways based on availability and scalability of web application.

1). In Process Mode:
This is default mode and useful for small application which is hosted on single server.
Advantages:
-Fastest mode.
-Simple configuration.
Disadvantages:
-Session data will be lost if worker process or application domain recycle.
-Not ideal for web garden and web form.

2). Out-of-process session mode(State server mode):
This mode is useful for highly available and scalable applications.Session state is stored in a process called aspnet_state.exe that runs as a windows service which listens on TCP port 42424 by default.
Advantages:
-Supports web farm and web garden configuration.
-Session data is persisted across application domain recycles.This is achieved by using separate worker process for maintaining state.
Disadvantages:
-Out-of-process mode provides slower access compared to in process.
-Requires serializing data.

3). Sql-Backed Session State: Session can also be stored in sql server database.Storing session in DB offers resilience that can serve session to a large web farm that persists across IIS restarts.SQL based session state is configured with aspnet_regsql.exe.
Advantages:
-Supports web farm and web garden configuration.
-Session State is persisted across application domain recycles and even IIS restarts.
Disadvantages:
-Required serialized of objects.