The Art of CTO Architecture Calculator estimates system capacity, scaling requirements, and infrastructure resource needs based on expected load, data volume, and performance targets.
Frequently Asked Questions
How do you estimate system capacity requirements?
Capacity estimation starts with defining expected peak load (requests per second, concurrent users, data throughput), then calculating the resources needed to handle that load with headroom. Account for compute (CPU cores based on request processing time), memory (working set size plus caching needs), storage (data growth rate over 1-3 years), and network bandwidth (payload sizes times request volume). Apply a 2-3x multiplier over average load to handle peaks and leave room for growth.
What is the difference between vertical and horizontal scaling?
Vertical scaling (scaling up) means adding more resources to a single server — more CPU, RAM, or faster storage. It is simpler but has hard limits and creates single points of failure. Horizontal scaling (scaling out) means adding more servers behind a load balancer. It offers near-unlimited capacity and better fault tolerance but requires stateless application design, distributed data management, and more operational complexity. Most modern architectures use horizontal scaling for compute and a combination for databases.