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ThinManage 3.1 Administration Manual

High Availability

The purpose of this section is to define the concept of High Availability (HA), outline the requirements for architecting an

HA-compliant system, and describe the strategies for deploying a highly available ThinManage system. This section will

also present possible failure scenarios and demonstrate how the high availability aspect of ThinManage overcomes each

of the hypothetical situations.

What is High Availability?

As defined by the IEEE, High Availability (HA for short) refers to the availability of resources in a computer system, in the

wake of component failures in the system

. High Availability is often associated with fault-tolerant systems.

Requirements

In order to achieve an HA-compliant system, ThinManage adheres to the following requirements:

1. Fault-Tolerant System: ThinManage has the ability to continue service despite a hardware or software failure.

Essentially, this means eliminating a single point of failure (SPOF) on the system and having failover capabilities.

The result of a single component failure does not disrupt service of the entire system.

2. Failover Capabilities: When one component in ThinManage fails resulting in a loss of service, the service is

started on another component in the system. This transfer of a service following a failure in the system is termed

failover.

3. Scalable: ThinManage is able to support multiple concurrent connection broker servers in order to balance heavy

loads.

4. Stateless: Each server treats each request as an independent transaction that is unrelated to any previous

request on that same server or another server.

Architectures

An administrator has the option to deploy ThinManage in two different ways. The first configuration is called the Basic

Architecture. This is a simple environment that consists of just one server, with one database repository. High availability,

along with its fault-tolerant characteristics, is not present with this type of architecture.

The second option is the Enterprise Architecture – a three-tiered configuration that provides a more robust environment

and includes all the benefits expected from an HA system. The Enterprise Architecture will be the primary focus of this

section.

IEEE Task Force on Cluster Computing, “High Availability (HA)” < http://www.ieeetfcc.org/high-availability.html>

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Devon IT HC12 Manual de usuario Pagina 51