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--- dido:99_annexes:annex-b-terms-and-definitions:s:scalability [2026/07/11 11:14] – removed - external edit (Unknown date) 127.0.0.1
+++ dido:99_annexes:annex-b-terms-and-definitions:s:scalability [2026/08/06 09:20] (current) – nick_dido
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+====== Scalability ======
+[[dido:99_annexes:annex-b-terms-and-definitions:start|Go up to Terms and Definitions]]
+===== Discussion =====
+Scalability is a [[dido:99_annexes:annex-b-terms-and-definitions:q:quality_characteristic|Quality Characteristic]] concerning the degree to which a subject maintains specified behavior as workload, size, volume, participation, complexity, or allocated resources change within defined limits.
+Scalability can apply to:
+  * A market
+  * A deployment
+  * A [[dido:99_annexes:annex-b-terms-and-definitions:c:candidate_solution|Candidate Solution]]
+  * A [[dido:99_annexes:annex-b-terms-and-definitions:d:distributed_system|Distributed System]]
+  * A [[dido:99_annexes:annex-b-terms-and-definitions:n:node|Node]]
+  * A Qualified Node
+  * A [[dido:99_annexes:annex-b-terms-and-definitions:n:node_set|Node Set]]
+  * A service
+  * A software component
+  * A data store
+  * A communication facility
+  * A governance process
+  * An [[dido:99_annexes:annex-b-terms-and-definitions:e:execution_facility|Execution Facility]]
+  * Another subject whose workload, size, participation, complexity, or allocated resources can change
+Changes relevant to Scalability can include changes to:
+  * Number of participants
+  * Number of [[dido:99_annexes:annex-b-terms-and-definitions:u:user|Users]]
+  * Number of Nodes
+  * Number of Node Sets
+  * Number of Qualified Nodes
+  * Number of governed functions
+  * Number of work events
+  * Number of Evidence References
+  * Number of Compensation Claims
+  * Number of jurisdictions
+  * Number of Settlement Instructions
+  * Number of transactions
+  * Number of requests
+  * Number of events
+  * Number of providers
+  * Number of service instances
+  * Data volume
+  * Evidence volume
+  * Message volume
+  * Settlement-record volume
+  * Processing rate
+  * Geographic distribution
+  * Duration of operation
+  * Governance complexity
+  * Another characteristic established by the [[dido:99_annexes:annex-b-terms-and-definitions:a:acceptance_criteria|Acceptance Criteria]]
+Allocated-resource changes can include changes to:
+  * Processor capacity
+  * Memory
+  * Storage
+  * Network capacity
+  * Number of service instances
+  * Number of Execution Facilities
+  * Number of [[dido:99_annexes:annex-b-terms-and-definitions:d:deployment_target|Deployment Targets]]
+  * Number of [[dido:99_annexes:annex-b-terms-and-definitions:o:operational_resource|Operational Resources]]
+  * Another allocated [[dido:99_annexes:annex-b-terms-and-definitions:r:resource|Resource]]
+Scalability can identify:
+  * The evaluated subject
+  * The initial workload, size, volume, participation, complexity, or resource allocation
+  * The changed workload, size, volume, participation, complexity, or resource allocation
+  * The applicable scaling direction
+  * The applicable scaling method
+  * The applicable scaling limits
+  * The applicable [[dido:99_annexes:annex-b-terms-and-definitions:t:test_environment|Test Environment]]
+  * The applicable [[dido:99_annexes:annex-b-terms-and-definitions:c:configuration|Configuration]]
+  * The characteristics required to remain within permitted limits
+  * The applicable measurement methods
+  * The applicable measurement units
+  * The required measurement precision
+  * The permitted tolerances
+  * The permitted degradation
+  * The applicable DIDO [[dido:99_annexes:annex-b-terms-and-definitions:b:baseline|Baseline]]
+  * The applicable [[dido:99_annexes:annex-b-terms-and-definitions:v:validation_criteria|Validation Criteria]]
+  * The applicable Acceptance Criteria
+  * Its [[dido:99_annexes:annex-b-terms-and-definitions:e:evidence|Evidence]]
+  * Its [[dido:99_annexes:annex-b-terms-and-definitions:p:provenance|Provenance]]
+  * Its [[dido:99_annexes:annex-b-terms-and-definitions:t:traceability|Traceability]]
+Technical scaling can be:
+  * Vertical
+  * Horizontal
+  * Manual
+  * Automated
+  * Upward
+  * Downward
+  * Temporary
+  * Persistent
+Vertical scaling changes the Resources allocated to an existing instance.
+Horizontal scaling changes the number of instances participating in the evaluated operation.
+In the Governed Node Service Market, Scalability supports:
+  * Ecosystem growth
+  * Expanded jurisdictional participation
+  * Increased provider participation
+  * Increased numbers of Qualified Nodes
+  * Increased governed work
+  * Larger Evidence volumes
+  * Increased Compensation Claim volume
+  * Increased Settlement Instruction volume
+  * Increased settlement-record volume
+  * Continued provider comparison
+  * Continued governance review
+A scalable Governed Node Service Market supports increased size, volume, participation, and complexity while preserving:
+  * Qualification discipline
+  * Functional obligations
+  * Non-functional obligations
+  * Jurisdictional obligations
+  * Policy obligations
+  * Governance obligations
+  * Evidence continuity
+  * Cost attribution
+  * Provider comparison
+  * Settlement Traceability
+===== Definition =====
+//[[dido:99_annexes:annex-b-terms-and-definitions:q:quality_characteristic|Quality Characteristic]] concerning the degree to which a subject maintains specified behavior as workload, size, volume, participation, complexity, or allocated resources change within defined limits//
+===== 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]]
+  * Financial Systems Archetype, Part 7: Governed Node Service Market
+  * [[dido:99_annexes:annex-b-terms-and-definitions:q:quality_characteristic|Quality Characteristic]]
+  * [[dido:99_annexes:annex-b-terms-and-definitions:p:performance_efficiency|Performance Efficiency]]
+  * DIDO Reference Implementation Conceptual Model
+  * DIDO-TE draft Requirements Register
+The original shared definition described Scalability as the ability of a market or deployment to support increased numbers of participants, Nodes, governed functions, work events, Evidence References, Compensation Claims, jurisdictions, and Settlement Instructions.
+This revision generalizes Scalability for use throughout the shared DIDO corpus while preserving the original Governed Node Service Market application.
+===== Note =====
+Scalability differs from capacity:
+  * Capacity identifies a maximum limit under specified conditions
+  * Scalability concerns behavior as workload, size, volume, participation, complexity, or allocated resources change within defined limits
+Scalability differs from [[dido:99_annexes:annex-b-terms-and-definitions:p:performance_efficiency|Performance Efficiency]]:
+  * Scalability concerns changes in behavior as evaluation conditions or allocated Resources change
+  * Performance Efficiency concerns performance relative to Resources used under specified conditions
+Performance Efficiency measurements can provide Evidence for a Scalability evaluation.
+Scalability differs from Elasticity:
+  * Scalability concerns the degree to which a subject accommodates changes in workload, size, volume, participation, complexity, or allocated Resources
+  * Elasticity concerns adaptation to changing conditions by activating, deactivating, adding, removing, or substituting Resources or Qualified Nodes
+Elasticity can be a mechanism for achieving Scalability. Scalability does not require automated adaptation unless the applicable Acceptance Criteria establish that requirement.
+Scalability differs from growth:
+  * Growth identifies an increase in size, volume, participation, or complexity
+  * Scalability concerns whether the subject maintains specified behavior while growth or another defined change occurs
+A subject is not scalable without qualification. A Scalability evaluation must identify:
+  * The characteristic that changes
+  * The evaluated range
+  * The required behavior
+  * The permitted degradation
+  * The applicable measurement conditions
+  * The applicable comparison method
+A subject can scale successfully in one dimension and unsuccessfully in another.
+For example:
+  * A Candidate Solution can scale with transaction volume but not with the number of geographically distributed Nodes
+  * A market can scale with the number of providers but not with the number of jurisdictions
+  * A governance process can scale with work-event volume but not with the number of required reviews
+  * A deployment can scale with processor capacity but not with storage volume
+Scalability does not mean every measured characteristic remains constant. The Acceptance Criteria establish the permitted variation and degradation as the evaluated conditions change.
+===== Example =====
+A Governed Node Service Market expands from one FX Demo jurisdiction to several jurisdictions.
+The number of:
+  * Participants
+  * Qualified Nodes
+  * Governed functions
+  * Work events
+  * Evidence References
+  * Compensation Claims
+  * Settlement Instructions
+increases during the evaluation period.
+The applicable Acceptance Criteria establish the required behavior, processing limits, response times, Evidence-continuity obligations, provider-comparison obligations, governance-review obligations, and Settlement Traceability requirements.
+The market exhibits Scalability when it supports the increased size, volume, participation, and complexity while continuing to satisfy those obligations.
+In a separate DIDO-TE evaluation, three Candidate Solutions process increasing transaction workloads under controlled resource allocations. DIDO-TE records performance, Resource Consumption, failures, and permitted degradation at each workload level.
+The resulting Test Results support a comparative evaluation of Candidate Solution Scalability.
+----
+<WRAP centeralign>
+© 2026 Dido Solutions, Inc. and Jackrabbit Consulting, Inc.
+</WRAP>