Types of installations
There are a number of different installation types for Perception Server. The type of installation chosen will depend on the needs of your organization. The installation types are highlighted below.
A single server installation has all the components installed on the same server, with or without the database server. All functionality for Perception is accessed through the single server. The diagram below shows a single server installation connecting to a database on another server.
Multi-tiered installations allow the different tiers within Perception to be installed on different servers to increase the through put of the application. For example, the software responsible for displaying questions and assessments to a participant can be installed on one computer, Enterprise Manager and the rest of Perception including the Questionmark Assessments Business Service on another. Finally the database holding the repository on a third. By spreading out the software to use 3 computers you can improve the reliability and speed of the application by dedicating computers to each of the most important functions.
The multi-tiered architecture of Perception Version 5 is composed of the following tiers:
- Database Tier - hosts the shared repository and stores questions, assessment and result data
- Business Logic Tier - sends assessment data from the database server to the presentation tier. This is known as the Questionmark Assessment Business Service (QABS) it includes the Enterprise Manager and Shared Repository Manager applications
- Presentation Tier - presents assessments to participants in a suitable format. This is known as the Questionmark Presentation Layer for Assessments (QPLA) and is what the participant connects to when they take an assessment
These 3 tiers combine to form Questionmark Perception.
Typically, most organizations split the tiers across various servers, as shown below.
Load balanced installations are usually a combination of multi-tiered or single server installations that work in tandem to provide better responsiveness under high loads or a redundancy if any server fails. Load balanced systems consist of a number of servers setup in the same manner that spread the work load. Incoming requests are sent to any machine in the load balanced cluster. This means that all the servers must be exact duplicates or be able to gather and record information to the same source. The diagram below highlights a simple load balanced system in operations.
For further information about the best practice for setting up Perception in a Load Balanced environment, please refer to the following: