Clusters provide system robustness that reduces or eliminates planned and unplanned downtime and ensures high performance with backup and failover functionality. If one component (hardware or software) in the system fails, another component in the cluster replaces it with minimal or no noticeable difference to users. In fact, users may see degraded performance but will not lose access to the service. Also, the workload in a cluster is automatically rebalanced when a failed server comes back online.

Clustering simplifies administrative maintenance because multiple servers are managed as a single system and all of the servers share a single dataset that includes related files and shared database access. Not only does this minimize required maintenance efforts, it also ensures that servers can be added or removed from the cluster without requiring reconfiguration and downtime.

Depending on the specific operating system or supplemental applications, clustering supports “rolling upgrades” that minimize disruptions in operations for planned downtime caused by maintenance or upgrades. During off-peak time, the workload can be shifted onto other servers within the cluster while the maintenance or upgrade is performed on the unloaded server.

The size or configuration of the cluster can easily be expanded or upgraded to more appropriately accommodate changing conditions and requirements of the organization. New components can easily be added as system load increases. Also, clustered content server configurations support limited horizontal scaling (multiple machines sharing a single dataset) to optimize overall throughput.

Consumption load can be distributed evenly among multiple instances of web servers within the cluster to ensure that no single device is overwhelmed. If one server starts to get overloaded, requests are forwarded to another server with available capacity. Load balancing schemes are especially important for cluster installations where it is difficult to predict the number of requests that will be issued to a server.

The content server can be configured to run in a decentralized, distributed environment as well as scale and search across multiple machines. The modular design allows organizations to split the main content server components across multiple servers to maximize system resources throughout the installation. For example, to relocate the content server processing, the underlying database and file system can reside on a server separate from other components.