High Availability and Load on the Services and Web Servers

In this scenario, you can maintain a Web Farm with Web Servers and a AVEVA Work Tasks Services cluster on separate machines while the Databases are installed on a different machine. This deployment provides scalability and high availability of the Workflow Engine and Web Servers. This is achieved by distributing the load equally among all the machines in the cluster and the Web Farm.

Multiple servers in the Web Farm or the cluster run the same services. Failure of a server does not impact other servers. You can take the affected server offline while the other servers maintain the service. This type of installation provides Failover. Thus allowing you to easily add or remove machines from the Web Farm or from the cluster without affecting the execution of workflows.

This is the optimal scenario for heavy load conditions and can be considered if you anticipate heavy load on the Workflow Engine or the Web Server.

See: Web Farm Connecting to Separate Services Cluster with Database on a Different Machine

In this scenario, you have a Web Server and the Services installed on the same machine. You can host this set up on multiple computers to form a Web Farm with clustered Services. The Databases are installed on a machine by itself. While scaling out, ensure that the machine has both the Web Server and the Services installed.

See: Web Server Farm with Clustered Work Tasks Services and Databases on Different Machines