R

Recovery Log

A file that maintains a history of all of the transactions affecting the cluster database on any of the cluster nodes. The recovery log is stored on the cluster's quorum resource and is also referred to as the quorum log.

Redundant Array of Inexpensive Disks (RAID)

A storage device that uses two or more magnetic or optical disks working in tandem to increase performance and provide various levels of error recovery and fault tolerance. RAID can be implemented in software using standard disk controllers, or it can be designed into the disk controller itself.

Reliability

Degree to which data in a transfer is guaranteed to arrive at its destination in its intended form. Reliability refers to three distinct attributes: (a) the degree to which a system or component achieves a transfer, (b) the degree to which a system or component can fail and the transfer still occur, and (c) the degree to which the integrity of the data is preserved.

Resource

Physical or logical entity owned and managed by a cluster node which can be brought online and taken offline. A resource can only be hosted on a single cluster node at any point in time.

Resource API

Set of functions that allow a resource DLL to communicate with the Resource Monitor. Some of the functions are implemented by a resource DLL and others are implemented by the Resource Monitor.

Resource class

Numeric value that is used to identify resources of similar capability, such as resources that can act as storage devices.

Resource DLL

Dynamic link library containing an implementation of the Resource API for a specific type of resource. The Resource DLL is loaded into the address space of its Resource Monitor.

Resource Manager

Software component in the Cluster Service that works with the Cluster Service's Failover Manager to manage resources and groups and initiate failover operations.

Resource Monitor

Cluster software component that manages communication between a node's Cluster Service and one or more of its resources.

Router

An intelligent hub that routes traffic to a designated channel.