13.1 Web Deployment Model

Web applications developed with Visual LANSA on Windows consist of three logical parts:

• Web Server (that is, IIS)

• Data Application server (that is, LANSA)

• Database Server (for example, SQL Server)

It is most common, even in high transaction environments, to locate the Database Server on a dedicated machine so that as much RAM as possible may be allocated to the database. The Web Server and Data Application Server are then installed together on a separate machine, again the RAM is largely available for the LANSA processes to execute in. In systems with a high throughput, multiple Web Server/App Server machines may be installed with a Load Balancer to share the load between them, or even a simple DNS round-robin multiple IP address setup to load balance between the servers.

Linux and IBM i servers may also host any part, or all, of the web host and distribution. Some common scenarios which involve a part of Windows and a part elsewhere are:

• Windows Web Server with IBM i Data Application Server and DB2 i Database Server.

• Linux Web Server with Windows Data Application Server and SQL Server Database Server.

• Windows Web Server and Data Application Server with Linux Oracle Database Server