Advantages of Replicating Data

The performance and availability problems associated with remote database access can be solved by replicating the data from its source database to a local database. Replication Server provides a cost-effective, fault-tolerant system for replicating data.

Replication Server keeps data up to date in multiple databases so that clients can access local data instead of remote, centralized databases. Compared to a centralized data system, a replication system provides improved system performance and data availability and reduces communication overhead.

Because it transfers transactions, not rows, Replication Server maintains the integrity of replicated data across the system, while also increasing data availability. Replication Server also allows you to replicate stored procedure invocations, further enhancing performance.

Improved Performance

In a distributed replication system, data requests are completed on the local data server without the client having to access the WAN. Performance for local clients is improved because:

LAN data transfer rates are faster than WAN data transfer rates.
Local clients share local data server resources instead of competing for central data server resources.
Traffic and contention for locks are considerably reduced because local decision-support applications are separated from centralized OLTP applications.

Greater Data Availability

In a distributed replication system, data is replicated at local and remote sites, so clients can continue to work regardless of what happens at the primary data source or over the WAN.

When a failure occurs at a remote site, clients can continue to use local copies of replicated data.
When a WAN failure occurs, clients can continue to use local replicated data.
When the local data server fails, clients can switch to replicated data at another site.

When WAN communications fail, Replication Servers at other sites store transactions in stable queues (disk storage) so that replicated tables at the unavailable site can be brought up to date when communications resume. When a replicated function is initiated in a source database, it is stored in stable queues until it can be delivered to the destination site.