Vanmathy distributed operating system
- 1. NADAR SARASWATHI COLLEGE OF ARTS&SCIENCE,THENI DEPARTMENT OF COMPUTER SCIENCE&INFORMATION TECHNOLOGY V.S.PRIYADHARSHINI I MSC(CS)
- 3. What is fault tolerance • Fault tolerance refers to the ability of a system (computer, network, cloud cluster, etc.) to continue operating without interruption when one or more of its components fail. • The objective of creating a fault-tolerant system is to prevent disruptions arising from a single point of failure, ensuring the high availability and business continuity of mission- critical applications or systems.
- 4. • Fault-tolerant systems use backup components that automatically take the place of failed components, ensuring no loss of service. These include: • Hardware systems that are backed up by identical or equivalent systems. For example, a server can be made fault tolerant by using an identical server running in parallel, with all operations mirrored to the backup server. • Software systems that are backed up by other software instances. For example, a database with customer information can be continuously replicated to another machine. If the primary database goes down, operations can be automatically redirected to the second database. • Power sources that are made fault tolerant using alternative sources. For example, many organizations have power generators that can take over in case main line electricity fails.
- 5. • Fault tolerance can play a role in a disaster recovery strategy. For example, fault-tolerant systems with backup components in the cloud can restore mission-critical systems quickly, even if a natural or human-induced disaster destroys on-premise IT infrastructure.
- 6. Fault tolerance vs. high availability • High availability refers to a system’s ability to avoid loss of service by minimizing downtime. It’s expressed in terms of a system’s uptime, as a percentage of total running time. Five nines, or 99.999% uptime, is considered the “holy grail” of availability. • In most cases, a business continuity strategy will include both high availability and fault tolerance to ensure your organization maintains essential functions during minor failures, and in the event of a disaster. • While both fault tolerance and high availability refer to a system’s functionality over time, there are differences that highlight their individual importance in your business continuity planning.
- 7. • Some important considerations when creating fault tolerant and high availability systems in an organizational setting include: • Downtime – A highly available system has a minimal allowed level of service interruption. For example, a system with “five nines” availability is down for approximately 5 minutes per year. A fault- tolerant system is expected to work continuously with no acceptable service interruption. • Scope – High availability builds on a shared set of resources that are used jointly to manage failures and minimize downtime. Fault tolerance relies on power supply backups, as well as hardware or software that can detect failures and instantly switch to redundant components. • Cost – A fault tolerant system can be costly, as it requires the continuous operation and maintenance of additional, redundant components. High availability typically comes as part of an overall package through a service provider (e.g., load balancer provider).
- 8. Load balancing and failover: fault tolerance for web applications • In the context of web application delivery, fault tolerance relates to the use of load balancing and failover solutions to ensure availability via redundancy and rapid disaster recovery.
- 9. Continue: • Load balancing solutions allow an application to run on multiple network nodes, removing the concern about a single point of failure. Most load balancers also optimize workload distribution across multiple computing resources, making them individually more resilient to activity spikes that would otherwise cause slowdowns and other disruptions.
- 10. • mperva load balancing and failover solutions • Imperva offers a complete suite of web application fault tolerance solutions. The first among these is our cloud-based application layer load balancer that can be used for both in- datacenter (local) and cross-datacenter (global) traffic distribution. • The solution is provided via a load balancing as a service (LBaaS) model and is delivered from a globally-distributed network of data centers for rapid response and added redundancy.
- 11. • Intelligent data-driven algorithms (e.g., least pending requests) are used to track server loads in real-time for optimized traffic distribution. • The other side of the coin is our failover solution that uses automated health checks from multiple geolocations to monitor the responsiveness of your servers.
- 12. How Does Fault Tolerance Work? • Fault tolerance can be built into a system to remove the risk of it having a single point of failure. To do so, the system must have no single component that, if it were to stop working effectively, would result in the entire system failing. • Fault tolerance is reliant on aspects like load balancing and failover, which remove the risk of a single point of failure. It will typically be part of the operating system’s interface, which enables programmers to check the performance of data throughout a transaction.
- 13. Components of a Fault-tolerance System • The key benefit of fault tolerance is to minimize or avoid the risk of systems becoming unavailable due to a component error. This is particularly important in critical systems that are relied on to ensure people’s safety, such as air traffic control, and systems that protect and secure critical data and high- value transactions.