In a distributed system, failure transparency refers to the extent to which errors and subsequent recoveries of hosts

Server (computing)

In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

 and services

Web service

A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...

 within the system are invisible to users and applications

Application software

Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...

.

For example, if a server fails, but users are automatically redirected to another server and never notice the failure, the system is said to exhibit high failure transparency.

Failure transparency is one of the most difficult types of transparency to achieve since it is often difficult to determine whether a server has actually failed, or whether it is simply responding very slowly. Additionally, it is generally impossible to achieve full failure transparency in a distributed system since networks are unreliable.

There is also usually a trade-off between achieving a high level of failure transparency and maintaining an adequate level of system performance. For example, if a distributed system attempts to mask a transient server failure by having the client try to contact the failed server multiple times, performance of the system may be negatively affected. In this case, it would have been preferable to have given up earlier and tried another server.

See also

• Byzantine fault tolerance
  Byzantine fault tolerance
  Byzantine fault tolerance is a sub-field of fault tolerance research inspired by the Byzantine Generals' Problem, which is a generalized version of the Two Generals' Problem....
  
  
• Intrusion Tolerance
  Intrusion Tolerance
  Intrusion tolerance is a Fault-tolerant design approach to defending information systems against malicious attack. Abandoning the conventional aim of preventing all intrusions, intrusion tolerance instead calls for triggering mechanisms that prevent intrusions from leading to a system security...
  
  
• Capillary routing
  Capillary routing
  In networking and in graph theory, capillary routing, for a given network, is a multi-path solution between a pair of source and destination nodes...
  
  
• Cluster (computing)
  Cluster (computing)
  A computer cluster is a group of linked computers, working together closely thus in many respects forming a single computer. The components of a cluster are commonly, but not always, connected to each other through fast local area networks...
  
  
• Data redundancy
  Data redundancy
  Data redundancy occurs in database systems which have a field that is repeated in two or more tables. For instance, in case when customer data is duplicated and attached with each product bought then redundancy of data is a known source of inconsistency, since customer might appear with different...
  
  
• Elegant degradation
  Elegant degradation
  Elegant degradation is a term used in engineering to describe what occurs to machines which are subject to constant, repetitive stress.Externally, such a machine maintains the same appearance to the user, appearing to function properly. Internally, the machine slowly weakens over time. Eventually,...
  
  
• Error detection and correction
  Error detection and correction
  In information theory and coding theory with applications in computer science and telecommunication, error detection and correction or error control are techniques that enable reliable delivery of digital data over unreliable communication channels...
  
  
• Fail-safe
  Fail-safe
  A fail-safe or fail-secure device is one that, in the event of failure, responds in a way that will cause no harm, or at least a minimum of harm, to other devices or danger to personnel....
  
  
• Fault-tolerant design
  Fault-tolerant design
  In engineering, fault-tolerant design is a design that enables a system to continue operation, possibly at a reduced level , rather than failing completely, when some part of the system fails...
  
  
• Fault-tolerant system
  Fault-tolerant system
  Fault-tolerance or graceful degradation is the property that enables a system to continue operating properly in the event of the failure of some of its components. A newer approach is progressive enhancement...
  
  
• Progressive Enhancement
  Progressive enhancement
  Progressive enhancement is a strategy for web design that emphasizes accessibility, semantic HTML markup, and external stylesheet and scripting technologies...
  
  
• Separation of protection and security
  Separation of protection and security
  In computer sciences the separation of protection and security is a design choice. Wulf et al. identified protection as a mechanism and security as a policy, therefore making the protection-security distinction a particular case of the separation of mechanism and policy principle.- Overview :The...
  
  
• Transparency (computing)
  Transparency (computing)
  Any change in a computing system, such as new feature or new component, is transparent if the system after change adheres to previous external interface as much as possible while changing its internal behaviour. The purpose is to shield from change all systems on the other end of the interface...