Cluster vS Grid

Standard

There are many differences between Grid and Clusters. The following table shows comparison of Grid and Clusters.

CHARACTERISTIC CLUSTER GRID
Population Commodity Computers Commodity and High-end computers
Ownership Single Multiple
Discovery Membership Services Centralized Index  and Decentralized Info
User Management Centralized Decentralized
Resource management Centralized Distributed
Allocation/ Scheduling Centralized Decentralized
Inter-Operability VIA and Proprietary No standards being developed
Single System Image Yes No
Scalability 100s 1000?
Capacity Guaranteed Varies, but high
Throughput Medium High
Speed(Lat. Bandwidth) Low, high High, Low

A cluster is a group of computers organized together to perform the same set of functions. For instance, you may have a cluster running your database software. Or you can have a cluster running your corporate e-mail server software.

A grid is a collection of resources. A grid can be composed of multiple clusters. In Oracle’s grid world, you can have a cluster of servers running the database software and a cluster of servers running the Application Server software. Since they are all in the grid, you can move resources from one cluster to another should demands dictate.

References:

Oracle RAC Cluster Tips by Burleson Consulting

Oracle Website