MACROMEDIA COLDFUSION 4.5-ADMINISTRING COLDFUSION..., Manual

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48 Administering ColdFusion Server
State Management and Server Clustering
When using ClusterCATS for ColdFusion to cluster Web servers, and you want to use
client variables, you must use an external repository to store client variables, since the
system registry, which is bound to an individual system, can’t be dynamically accessed
by any other system.
Configuring a data source in a clustering environment
Like any other ColdFusion data source, the data source you specify to store your client
variables can live anywhere on your network that is accessible to ColdFusion. When
you add a new data source to ColdFusion for storing client variables (we recommend
dedicating a data source for this purpose rather than using an existing data source) you
can enable an option for ColdFusion to automatically create the tables necessary for
storing client variables.
However, in a cluster of servers all accessing the same data source for client variables,
ColdFusion only needs to create the necessary tables once. As you add the client
variables data source to each ColdFusion Server in the cluster, you do not need to
choose the option to have ColdFusion create the tables necessary to support client
variables, since they have already been created when you added the data source for the
first server in the cluster. If you inadvertently enable the option to automatically create
client variable database tables, ColdFusion generates a SQL error.
Enabling External Client State Management
You enable client state management in the ColdFusion Server using the Administrator
to specify a data source repository where you want to store client variables.
Although you can select and use an existing data source to store client variables, Allaire
recommends creating a new data source specifically for the purpose of storing client
variables. By separating data sources, you can more easily define security options for
the data sources used in your ColdFusion environment.
When creating a new data source for client variables, you do not need to create any
tables in the data source. ColdFusion automatically creates the tables necessary to
store client variables.
To create a client variable data source:
1. Open the ColdFusion Administrator to the Data Sources page.
2. Enter a data source name in the text entry box and click Add.
3. In the Create Data Source page, enter information about the new data source
location (path) as well as other options.
Excel and Text data sources do not appear as valid data sources for use in
configuring an external client data source repository. Neither data source type