Fault tolerance refers to the potential of a system(Cloud cluster, network, computer) which leads it to keep operating without interruption in case of failure of one or more of its components.
The main purpose of establishing fault tolerant ecosystems is to avoid disruptions caused by a single point of failure. Also , to ensure business continuity and maximum availability of mission critical applications.
Fault torrent systems are actually designed to automatically fulfill the duties performed by failed components and avoiding loss of service. It includes:
Hardware equipment backed up by identical systems. For instance, a server can be built fault tolerant by using identical servers in parallel such that all operations are mirrored to the backup server.
Those software systems which are backed up by software instances. For instance: databases can be cloned into other machines. If the main database goes down due to any reason then operations can be easily redirected to the second database.
Secondly, power resources could be made fault tolerant. For instance: organizations have power generators which ensure continuous power supply during power breakdowns.
Similarly, any component could be made fault tolerant using redundancy. Having a fault tolerance policy could play an important role in disaster recovery. Fault tolerant systems with backup equipment in the cloud may help in restoring mission critical systems. It is helpful in human induced disasters that destroy IT infrastructure.
Fault Tolerance and High availability:
High availability of any stem refers to its ability to avoid loss of service by minimum downtime. Usually it is measured by the system’s uptime.
99.99% uptime is considered the highest time of availability of any system.
Generally, a business continuity strategy includes high availability and fault tolerance in order to make sure the organization keeps essential functions during small failures and incase of any disaster.
Fault tolerance and high availability both refer to system’s functionality over time. There are few differences as well which highlight importance in business continuity planning.
To better understand difference between fault tolerance and high availability consider the example of twin engine airplane which is a fault tolerant system
If one engine stops working then another engine automatically gets in action. Similarly, a spare tire may help in minimizing downtime because the tyre can be replaced as soon as possible .
You may consider if creating fault tolerant and high availability systems in organization setting:
There are few factors which should be considered if you are creating tolerant and high availability systems in organization:
It refers to a highly available system that keeps working with minimal level of service interruption. For instance: a system having availability time with five nines could be down for maximum 5 minutes an year. Ideally a fault tolerant system will work without interruption of service.
High availability established on shared resources are merged for failures and downtime management. Fault tolerance is dependent upon power supply backups and the hardware as well as software which detects failures and switches to redundant components.
Sometimes a fault tolerant system can be expensive as it needs full operation and maintenance of additional redundant components. High availability usually comes as part of the overall package through service providers.
Few systems require fault tolerant design with high availability. System’s tolerance to service interruptions should be considered. The cost of interruptions with existing SLA agreements , cost and completing of implementation should also be considered.
Load balancing and Failover:
In web application delivery, fault tolerance is related to use of load balancing and fail over solutions for ensuring availability by redundancy and rapid disaster recovery. .
Load balancing and failover are actually inegal parts of fault tolerance. Load balancing enables you to run an application on different network nodes. Hence a single point of failure no longer remains an issue. Load balancers optimize workload distribution in different computing resources. Hence they can bear activity spikes. Otherwise, they may cause slowdowns and various interruptions.
Load balancing also helps in partial network failures. A system which contains two production servers utilizes a load balancer for automatically shifting workloads in case of server failure.
Failover solutions are used when there is a complete network failure during extreme scenarios. A failover system usually gets charged with auto activating a secondary platform for keeping web applications running meanwhile IT teams bring back the primary network online.
If you want to have a true fault tolerance system with zero downtime then you should use a hot failover strategy which transfers workload instantly to a working backup system. If you can’t have a constantly active standby system then you should use warm or cold failover. In this type of failover, the system takes time to load and starts workloads.
In the Cloud computing world, you can’t survive without a fault tolerant system. If your company needs dedicated servers then you should be on board with a reputable hosting company which provides backup support through fault tolerant systems,