The systems that aim to be used full-time and prevent the closure of the network as a result of any interruption or error are called High Availability systems. Such systems have redundant hardware and software that make the system usable despite failures. Well-designed systems with High Availability prevent even the smallest errors from occurring.
Any hardware or software component that may fail has the same type of backup component. When a failure occurs, the failover operation takes control of the system and moves the operation performed by the failed component to the backup component. This process reorganizes system-wide resources and recovers partially or completely failed operations. It then returns the system to normal within a minimum period of time, preferably in microseconds. There is no need for the user to take any action while these are happening. The system works automatically.
System Design Principles
Software engineers use three system design principles to help achieve high availability:
- Elimination of single-point failure; It is the part that will stop the entire system from working if the single points of failure fail. This is undesirable in any system with the goal of high availability or reliability. Therefore, the first goal of developers is to eliminate these errors.
- Detection of reliable transition or failover points
- Fault detection capabilities
High data access and storage availability are often used in government, healthcare and other legitimate industries. High availability systems automatically recover from server or component failure. No matter how reliable your systems and software are, problems can arise that can crash your applications or servers. It is essential that the systems can handle increased loads and high traffic levels, and identify possible points of failure and reduce downtime. All software, including the operating system and the application itself, must be prepared to deal with unexpected malfunctions. Highly available servers must be resistant to power outages and hardware failures, including hard drives and network interfaces. In practice, there are several components to consider, such as data quality, environmental conditions, hardware scalability, and strategically reliable networks and software, to ensure high availability.
High Availability Planning
System planning consists of two stages.
- Capacity Planning: In order for a highly available system to be considered fully usable, operations must be processed in a timely manner. The capacity of the system is important for this. Therefore, the application must have sufficient resources. Nodes must be added to the system to increase capacity and manage application growth. In other words, by clustering the data, maximum use of capacity is achieved with minimum intervention.
- Backup Planning: It means replication of system components so that a single component failure does not extend the downtime of the system. Spare components are often used in high-quality machines to protect against failures. Examples of these are redundant power supplies and redundant cooling fans. An architectural network is established and provided for the uninterrupted operation of the system.
Leading companies working in the field of High Availability
- Rocket iCluster
- Sentry Software