Scalability

The array software provides scalability by implementing a protocol that responds dynamically to changes in array membership. At a frequent and regular interval, the array daemon multicasts information messages over the control network. These information messages are, at once, a heartbeat and a means of conveying "health" information about each host.

When a host is removed--for example, if a machine is receiving a software upgrade--within milliseconds, the array detects the machine's absence and removes the machine's service address(es) from availability. Similarly, if a machine is added to the array, nearly immediately, the array detects the new host and makes its service address available for incoming client requests.