Place all computing resources for a service on a single server. If the server fails, the entire service fails.
Sun provides high-end servers that provide the following benefits:
Replacement and reconfiguration of hardware components while the system is running
Ability to run multiple applications in fault-isolated domains on the server
Ability to upgrade capacity, performance speed, and I/O configuration without rebooting the system
A high-end server typically costs more than a comparable multi-server system. However, a single server provides savings on administration, monitoring, and hosting costs for servers in a data center. Load balancing, failover, and removal of single points of failure is more flexible with multi-server systems.