Clustered System in OS
Overview of Cluster System
Clustered Operating Systems resembles parallel operating systems as they possess multiple CPUs. However, a cluster is created when two or more computer systems are merged. Primarily, in a cluster, computers share common storage, and the system works together.
To make a cluster operating system function efficiently, there exists two clusters: hardware and software cluster. A hardware cluster enables high-performance disk sharing between systems, while the software cluster allows all systems to work together.
Every node of a cluster system has cluster software which is responsible for monitoring the operations of the cluster system. In case any of the cluster nodes fails, then the rest of the nodes takes control of all its storage and resources and restarts the functioning of the cluster system.
Types of Cluster Systems
Primarily, there exists two types of cluster systems:
- Symmetric Cluster: In this type of clustering, all the nodes run applications and monitor other nodes at the same time.
- Asymmetric Cluster: In this type of clustering, one of the nodes is in a hot standby mode, while rest all nodes run different applications. The node which is in hot standby mode continuously monitors the entire cluster and act as a replacement if any of the nodes fails.
- Parallel Cluster: These clusters enable multiple users to access the same data on the shared storage. It is accomplished by using special software versions and applications.
Classification of Clustered Systems on its Operations
Clustered Systems can be used for several purposes as listed below:
- Load Balancing clusters: In this type of cluster, nodes share the workload for load balancing which enhances the system performance.
- High Availability: To increase the availability of the clustered system, additional nodes are present in the cluster. These extra nodes are put to use when any of the existing nodes fails. These clusters are known as failover clusters or HA clusters.
Advantages of Clustered System
The benefits of clustered system are:
- High Performance
- Increased fault tolerance
- High scalability
Disadvantages of Clustered System
The limitations of clustered system are:
- Expensive to implement
- System establishment, monitoring, and maintenance is complex