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18. Glossary

SPOF

Single Point of Failure: a part which renders an entire system unusable when if fails.

MAC Address

Ethernet hardware address.

SSA

Serial Storage Architecture: a disk attach technology promoted by the SSA Industry Association.

SCSI

Small Computer System Interface: the standard disk technology in small and midrange systems.

EIDE

Enhanced Integrated Drive Electronics: the standard disk technology for the PC market.

Business Critical

An Entity which is critical to business success, e.g. the data processing equipment of a company. Also named "mission critical".

Cluster Node

A host in a cluster.

Idle Standby

A simple redundancy setup where one cluster node is idly supervising the other (active) node.

Simple Fallover

A slightly more complex redundancy setup where the standby node is doing less important work which is not taken over by any other cluster node.

Mutual Takeover

A redundancy setup where both nodes do business critical work, being a standby for each other.

Rotating Standby

A redundancy setup where one node does business critical work and the other is the standby node. Both change their roles after a failure of the active node.

Concurrent Access

A redundancy setup where all nodes access the resource group including the external disks concurrently with help of a distributed lock manager.

Heartbeat

Communication method in a loosely coupled cluster to exchange status and keepalive data.

Raw Disk Devices

Unbuffered I/O devices which make sure data is actually written to disk during a write operation.

IPAT

Abbreviation for IP Address Takeover


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