Product Catalog System
In the Commerce Server Product Catalog System, you can make the Catalogs database redundant by installing it on multiple Web servers fronted by a single-IP solution. In this configuration, a computer running SQL Server publishes product catalogs to subscribing computers running SQL Server (the production computers). The subscribers have read-only versions of the product catalogs, and are load balanced using Network Load Balancing (NLB).
Since only one connection string is supported, this configuration requires a hosts file on the server running Commerce Server Business Desk to reference the SQL Server publisher instead of the subscribers.
Small installation. Use either active-active or active-passive clustering. This configuration supports two nodes running Microsoft Windows 2000 Server or four nodes running Microsoft Windows 2000 Datacenter Server.
Large installation. Use NLB to cluster servers running SQL Server and to provide a single, virtual database name for the Catalogs database business logic to access.
Or, you can use SQL Server replication (either snapshot or transaction, depending on your requirements) to maintain data consistency among servers running SQL Server.
The following figure shows how a configuration using NLB might look. In practice, NLB has been tested with a cluster containing as many as eight servers running SQL Server.
.gif "A figure that shows a Catalogs database cluster using NLB")
Very large installation. Put a single-IP solution in front of multiple NLB clusters. The following figure shows what the structure of a Catalogs database might look like for a very large installation.
.gif "A figure that shows the structure of a Catalogs database for a very large site")
The Product Catalog System maintains a continuous connection to database tables. If the connection is lost due to network or database problems, the Product Catalog System attempts to reestablish the connection.
Access to the Catalog database is initialized in the Application_OnStart function in Global.ASA. Subsequently, the Web application accesses product catalog information through the CatalogManager object, which in turn accesses the Catalog database. The CatalogManager object has the following single-point-of-failure dependencies:
- The AppConfig object (to find the catalog database connection string)
- The Administration database
- The Catalog database (to retrieve schema and data)
- The NTFS file system (to import and export the catalog XML file)
See Also
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