Distributed Systems
An architectural paradigm where multiple independent computers coordinate to appear as a single coherent system to users.
Classification
- ComplexityHigh
- Impact areaTechnical
- Decision typeArchitectural
- Organizational maturityIntermediate
Technical context
Principles & goals
Use cases & scenarios
Compromises
- Data inconsistencies due to network partitions
- Hidden performance bottlenecks and thundering herd
- Lack of resilience measures can cause cascading failures
- Explicit and documented consistency requirements
- Careful partitioning by domain and data access patterns
- Automated monitoring and regular resilience tests
I/O & resources
- Architectural requirements and SLAs
- Network and infrastructure overview
- Data access and consistency requirements
- Design decisions on partitioning and replication
- Operationalized deployment and observability pipelines
- SLA-compliant operational guidelines
Description
Distributed systems are collections of independent computers that appear to users as a single coherent system. They enable scalability, fault tolerance and geographic distribution but introduce concurrency, consistency and coordination challenges. Design requires trade-offs among performance, availability and complexity across networked nodes.
✔Benefits
- Scalability through horizontal expansion
- Increased fault tolerance and resilience
- Geographic proximity to users reduces latency
✖Limitations
- Complexity in design, testing and operations
- Challenges achieving strong consistency across partitions
- Increased need for observability and debugging tools
Trade-offs
Metrics
- Average response time
Average duration for requests across distributed components.
- Error rate
Proportion of failed requests or operations.
- Replication lag
Time difference between primary and replicated state.
Examples & implementations
Global key-value database
A distributed database uses replication and sharding to achieve global availability.
Service mesh in a microservices architecture
A service mesh manages communication, security and observability between distributed services.
Distributed stream processing with exactly-once semantics
Stream processors and cooperative consumers ensure consistent processing under partitions.
Implementation steps
Analyze requirements and choose consistency models
Partition the system into components and responsibility boundaries
Implement replication, sharding and failover strategies
Introduce observability and chaos testing
⚠️ Technical debt & bottlenecks
Technical debt
- Ad-hoc replication logic without documentation
- Monolithic database singleton as a bottleneck
- Incomplete test coverage for partition scenarios
Known bottlenecks
Misuse examples
- Attempting to enforce strong consistency without coordination
- Scaling by indiscriminately replicating all data
- Ignoring network partition tests in QA
Typical traps
- Underestimating operationalization costs
- Neglecting observability before production
- Missing rollback strategies for schema or process changes
Required skills
Architectural drivers
Constraints
- • Limited bandwidth and variable latencies
- • Regulatory requirements for data locality
- • Heterogeneous infrastructure and operations teams