public:99_annexes:annex-b-terms-and-definitions:r:recoverability

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public:99_annexes:annex-b-terms-and-definitions:r:recoverability [2026/09/12 17:42] – removed - external edit (Unknown date) 127.0.0.1public:99_annexes:annex-b-terms-and-definitions:r:recoverability [2026/09/12 17:43] (current) – ↷ Links adapted because of a move operation nick_dido
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 +====== Recoverability ======
  
 +[[public:99_annexes:annex-b-terms-and-definitions:start|Go up to Terms and Definitions]]
 +
 +===== Discussion =====
 +
 +Recoverability is a [[public:99_annexes:annex-b-terms-and-definitions:q:quality_characteristic|Quality Characteristic]] concerning the degree to which a subject can restore an affected state and required information after an interruption or failure.
 +
 +Recoverability can apply to:
 +
 +  * A [[public:99_annexes:annex-b-terms-and-definitions:c:candidate_solution|Candidate Solution]]
 +  * A [[public:99_annexes:annex-b-terms-and-definitions:d:distributed_system|Distributed System]]
 +  * A [[public:99_annexes:annex-b-terms-and-definitions:n:node|Node]]
 +  * A [[public:99_annexes:annex-b-terms-and-definitions:n:node_set|Node Set]]
 +  * A service
 +  * A software component
 +  * A hardware component
 +  * A data store
 +  * An [[public:99_annexes:annex-b-terms-and-definitions:e:execution_facility|Execution Facility]]
 +  * An [[public:99_annexes:annex-b-terms-and-definitions:o:operational_resource|Operational Resource]]
 +  * Another subject requiring restoration after an interruption or failure
 +
 +Recovery can concern restoration of:
 +
 +  * Operational state
 +  * Processing state
 +  * Transaction state
 +  * Stored information
 +  * Configuration
 +  * Communication
 +  * Service availability
 +  * Node participation
 +  * Node Set membership
 +  * Evidence
 +  * Provenance
 +  * Traceability
 +  * Another required state or information set
 +
 +Recoverability can identify:
 +
 +  * The evaluated subject
 +  * The interruption or failure condition
 +  * The state preceding the interruption or failure
 +  * The affected state
 +  * The required restored state
 +  * The affected information
 +  * The required restored information
 +  * The recovery starting event
 +  * The recovery completion event
 +  * The recovery method
 +  * The permitted recovery duration
 +  * The permitted information loss
 +  * The permitted state loss
 +  * The permitted service interruption
 +  * The required recovery verification
 +  * The applicable [[public:99_annexes:annex-b-terms-and-definitions:t:test_environment|Test Environment]]
 +  * The applicable [[public:99_annexes:annex-b-terms-and-definitions:c:configuration|Configuration]]
 +  * The applicable DIDO [[public:99_annexes:annex-b-terms-and-definitions:b:baseline|Baseline]]
 +  * The applicable [[public:99_annexes:annex-b-terms-and-definitions:v:validation_criteria|Validation Criteria]]
 +  * The applicable [[public:99_annexes:annex-b-terms-and-definitions:a:acceptance_criteria|Acceptance Criteria]]
 +  * Its [[public:99_annexes:annex-b-terms-and-definitions:e:evidence|Evidence]]
 +  * Its [[public:99_annexes:annex-b-terms-and-definitions:p:provenance|Provenance]]
 +  * Its [[public:99_annexes:annex-b-terms-and-definitions:t:traceability|Traceability]]
 +
 +Recoverability can be evaluated using measures such as:
 +
 +  * Recovery success rate
 +  * Recovery duration
 +  * Amount of information lost
 +  * Amount of state lost
 +  * Number of operations requiring repetition
 +  * Percentage of Evidence preserved
 +  * Percentage of transactions restored
 +  * Time required to restore service
 +  * Time required to restore Node Set participation
 +  * Another measure established by the Acceptance Criteria
 +
 +===== Definition =====
 +
 +//[[public:99_annexes:annex-b-terms-and-definitions:q:quality_characteristic|Quality Characteristic]] concerning the degree to which a subject can restore an affected state and required information after an interruption or failure//
 +
 +===== Source =====
 +
 +Adapted from:
 +
 +  * [[https://www.iso.org/standard/78176.html|ISO/IEC 25010:2023, Systems and software Quality Requirements and Evaluation (SQuaRE) — Product quality model]]
 +  * [[https://www.iso.org/standard/35747.html|ISO/IEC 25023:2016, Systems and software Quality Requirements and Evaluation (SQuaRE) — Measurement of system and software product quality]]
 +  * [[public:99_annexes:annex-b-terms-and-definitions:q:quality_characteristic|Quality Characteristic]]
 +  * [[public:99_annexes:annex-b-terms-and-definitions:r:reliability|Reliability]]
 +  * DIDO Reference Implementation Conceptual Model
 +  * DIDO-TE draft Requirements Register
 +
 +ISO/IEC 25010 identifies Recoverability as a Reliability-related product-quality subcharacteristic concerning restoration of affected information and state following interruption or failure.
 +
 +This definition adapts Recoverability for DIDO-TE evaluation of Candidate Solutions, Distributed Systems, Nodes, Node Sets, services, data stores, Execution Facilities, and Operational Resources.
 +
 +===== Note =====
 +
 +Recoverability differs from [[public:99_annexes:annex-b-terms-and-definitions:r:reliability|Reliability]]:
 +
 +  * Reliability concerns performance of specified functions under specified conditions for a specified period
 +  * Recoverability concerns restoration after an interruption or failure
 +
 +Recoverability contributes to Reliability but does not replace Reliability.
 +
 +Recoverability differs from availability:
 +
 +  * Availability concerns whether a subject is operational and accessible when required
 +  * Recoverability concerns restoration of affected state and information after interruption or failure
 +
 +Recoverability differs from fault tolerance:
 +
 +  * Fault tolerance concerns continued operation despite a fault
 +  * Recoverability concerns restoration after operation has been affected
 +
 +Recoverability does not necessarily require restoration to the exact state immediately preceding the interruption or failure.
 +
 +The applicable Acceptance Criteria can permit restoration to:
 +
 +  * The immediately preceding state
 +  * The most recent verified state
 +  * A defined checkpoint
 +  * A controlling Baseline
 +  * A safe state
 +  * Another approved state
 +
 +A restart does not by itself demonstrate Recoverability. Verification must determine whether the required state, information, service, Evidence, Provenance, and Traceability were restored.
 +
 +The applicable Acceptance Criteria should distinguish:
 +
 +  * Recovery of the evaluated subject
 +  * Recovery of the Test Environment
 +  * Recovery of DIDO-TE
 +  * Recovery of an Execution Facility
 +  * Recovery of a supporting Operational Resource
 +
 +===== Example =====
 +
 +DIDO-TE interrupts a Candidate Solution while it processes a controlled set of transactions.
 +
 +The Acceptance Criteria establish:
 +
 +  * The interruption event
 +  * The state required before interruption
 +  * The permitted recovery method
 +  * The maximum recovery duration
 +  * The maximum permitted transaction loss
 +  * The required restored Configuration
 +  * The required Evidence and Traceability
 +
 +After the interruption, the Candidate Solution restores its state and resumes processing.
 +
 +DIDO-TE compares the restored state, retained transactions, recovery duration, and preserved Evidence with the Acceptance Criteria.
 +
 +The resulting Test Results support evaluation of Candidate Solution Recoverability.
 +
 +----
 +
 +<WRAP centeralign>
 +© 2026 Dido Solutions, Inc. and Jackrabbit Consulting, Inc.
 +</WRAP>