Capacity Planning

Workflows

• Baseline: Measure current resource usage
• Forecast: Project future growth
• Size: Calculate required resources
• Buffer: Add headroom for spikes
• Monitor: Track actual vs. predicted

Key Metrics

Compute

• CPU utilization (target: 60-70%)
• Memory usage
• Request latency (P50, P95, P99)

Storage

• Disk IOPS
• Throughput (MB/s)
• Capacity growth rate

Network

• Bandwidth utilization
• Connection counts
• Packet loss

Estimation Framework

Little’s Law

L = λ × W

L = Average number of items in system
λ = Average arrival rate
W = Average time in system

Example Calculation

Given:
- 1000 requests/second
- 100ms average response time

Required concurrent connections:
L = 1000 × 0.1 = 100 concurrent connections

Resource Sizing

Database Connections

connections = (requests_per_second × avg_query_time) × 1.5

Memory

memory = (concurrent_users × memory_per_user) + base_overhead

CPU Cores

cores = (peak_rps × cpu_time_per_request) / target_utilization

Growth Planning

Traffic Growth

• Historical growth rate
• Planned marketing/launches
• Seasonal patterns

Data Growth

• Records per day
• Record size
• Retention policy

Capacity Planning Document

1. Current state metrics
2. Growth assumptions
3. Resource projections (3, 6, 12 months)
4. Cost estimates
5. Scaling triggers and thresholds