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SQL Anywhere 10.0.1 » SQL Anywhere Server - Database Administration » SQL Anywhere High Availability

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Using the SQL Anywhere Veritas Cluster Server agents

A cluster is a group of computers, called nodes, that work together to run a set of applications. Clients connecting to applications running on a cluster treat the cluster as a single system. If a node fails, other nodes in the cluster can automatically take over the services provided by the failed node. Clients may see a slight disruption in availability (the time it takes to resume the services on the remaining nodes), but are otherwise unaware that the node has failed.

When you use clustering with SQL Anywhere, any uncommitted transactions are lost when a database or database server fails over to another node in the cluster, and clients must reconnect to the database after failover occurs.

SQL Anywhere supports a variety of cluster environments where the cluster software can make any application into a generic resource subject to automatic failover so that high availability can be provided. However, only the database server process can be failed over, and the monitoring and control processes are limited.

For more information, see [external link]

Most cluster software provides an API for creating custom resources tailored to a specific application. SQL Anywhere includes two custom failover resources for Veritas Cluster Server: SAServer and SADatabase. The SAServer agent is responsible for database server failover, while the SADatabase agent is responsible for the failover of a specific database file. You can use one or both agents, depending on your application.

Your systems must be set up as follows to use the SQL Anywhere Veritas Cluster Server agents:

There are three ways to configure and add a new agent to Veritas Cluster Server:

  1. Using the Cluster Manager.

  2. Using command line utilities.

  3. Using a text editor and editing the configuration files.

The instructions in the following sections use the Cluster Manager.

For information about the available utilities, see Veritas Cluster Server Administration Guide

If you want to configure manually using a text editor, you must stop all Veritas Cluster Server services before editing the file. Otherwise, the changes will not take effect.

Configuring the SAServer agent
Configuring the SADatabase agent