Software Tolerance

In this article, we will discuss software fault tolerance starting from fault tolerance in general to the advantages and disadvantages of fault tolerance. So, let’s go a little bit deep into this article to understand the concept well. 

Fault Tolerance :
Fault Tolerance is a terminology that explains a software continues to perform its system operation even after the failure of its components. Software fault tolerance is the capability of the software to detect and recover from a fault that is occurring or has already occurred in either the software or hardware in the system in which the software is running in order to provide assistance in line with the parameters. Software fault tolerance is essential equipment in order to construct the next generation of highly available and reliable computing systems from embedded systems to data warehouse systems. Software fault tolerance is not just a solution, however, it has become an important component that needed to be included during the development of future generation systems.

Software faults have mostly occurred during the development of software. Software manufacturing, the replication of software, is considered to be accurate. The systems which are designed based on the fault-tolerance property are supposed to be less problematic in functioning the requirements.

Software Fault Tolerance Techniques :

• Hardware Fault-tolerance Techniques
• Software Fault-tolerance Techniques

Software Faults :
Design faults occur when a designer, either misinterprets the requirements given by the client or simply makes a mistake. Software faults are frequent for the usual reason that the complexity in modern systems is often reverted into the software part of the system. It is observed that 70-85% of present computer faults are from software errors.  Software faults may also occur from hardware; these faults are usually transient in nature and can be included using a combination of present software and hardware fault tolerance techniques.

How to apply Fault Tolerance :
Fault-tolerant systems consist of many components which are used as backup when the failure occurs in the system. These include:

1. Physical Systems –
   It is backed up by identical or equivalent systems. For example, a server can make use of the fault-tolerant property by using the same configuration server running in parallel, with all operations imitate the backup server.
2. Virtual Systems –
   It is reserved by other software instances. For example, a database with customer information can be continuously stored on another machine. If the current database occurs failure, then operations can be automatically redirected to the stored database.

What is Fault Tolerance Architecture?
There is a different way to create a fault-tolerant server platform and thus prevent data loss and avoid unplanned downtime. Fault tolerance in computer architecture simply describes what decisions are taken by the administrators and engineers so that the system remains functioning even in the case of failure. 

There are different fault tolerance tools available that can be considered for development. At the drive controller level, a redundant array of inexpensive disks (RAID) is a usual fault tolerance strategy that can be implemented while developing. Various facility-level forms of fault tolerance are available, which include cold, hot, warm, and duplicate sites. Fault tolerance computing plays a great role during disaster recovery and outage. For this reason, a fault tolerance strategy also includes some uninterrupted power supply (UPS) such as a generator, which runs independently even after the failure of the grid occurs. Byzantine fault tolerance (BFT) is another problem for future fault-tolerant architecture. BFT systems are necessary to the blockchain, nuclear power, and space industries because these systems prevent downtime even if certain nodes in a system failure or are driven by malicious actors.

Advantages of fault tolerance :

• This is a system that aims to provide more than one copy of the same system and switch to the other available copy in the case the system fails.
• If one of the systems fails, a stored copy of the same system can be used to test other functionalities of the system in a new environment without interfering with the core system.
• Using this strategy even if there is a failure at a single part of the system, the whole system will continue to work.
• Various levels of fault tolerance applications can protect a system from malicious attacks and hacking.
• Redundancy Having the same copy of the same system copied over in different locations can automatically be implemented when the main system fails.

Disadvantages of fault tolerance :

• There are certain conditions where during the development process if a failure occurs then working in the backup system causes different errors.
• As to protect the data from loss during a failure, we have to buy the components separately for present use and backup purpose which leads to an increase in cost for buying different components.
• A fault-tolerance design makes use of different less secure components which can lead to different security problems.