Glossary 39

failover (cluster)

1.The process that takes place when one controller in a dual-redundant configuration assumes the workload of a failed companion controller. Failover continues until the failed controller is repaired or replaced.

2.The process that takes place when the operation of a cluster group moves from one cluster node to another node in the same cluster.

fault tolerance

The ability of a system or component to continue normal operation when a fault (or failure) is encountered. Tolerance is achieved primarily by designing redundant elements into the system.

Fibre Channel

An IEEE standard for providing high-speed data transfer among workstations, servers, mainframes, supercomputers, desktop computers, storage devices, and display devices.

Gigabit Interface Converter-Shortwave

A device that converts electrical signals to optical signals at the point where the fiber cables connect to the Fibre Channel elements, such as controllers or adapters.

heartbeat

A signal transmitted between cluster nodes to indicate whether the nodes are operating.

high availability

A term used to identify a computer system that can continuously deliver services to its clients 99.9 % of the time (no more than 8.5 hours of downtime per year).

host

The primary or controlling computer in a system of computers connected by communication links.