Most servers are sized by guesswork: a number someone picked at launch, increased in a hurry after the first outage. Capacity planning replaces the guess with measurement.
Measure what you use
Collect at least a few weeks of data, including your busiest periods:
- CPU: average and peak utilisation, and how long peaks last.
- Memory: how much is used by applications versus cache, and whether the server ever swaps.
- Storage: space used and its growth per month, plus input/output operations and latency.
- Network: bandwidth at peak and monthly transfer.
- Application signals: response times, queue lengths, database connections.
Peaks matter more than averages. A server at 30% on average and 100% every evening is undersized.
Find the bottleneck
Performance problems usually have one limiting resource. Adding CPU to a server that is waiting on its disk achieves nothing. Look for the resource that saturates first when the service slows down.
Plan for growth and events
- Trend: how fast are users, data and traffic growing month by month?
- Events: product launches, campaigns, seasonal peaks, end-of-month processing.
- Headroom: keep enough spare capacity to absorb a peak and a failure at the same time, for example running at no more than 60 – 70% at normal peak.
Scale up or out?
- Scale up: a bigger server. Simple, but there is a ceiling, and the server remains a single point of failure.
- Scale out: more servers behind a load balancer. Better resilience and room to grow, but the application must support it.
Review regularly
Revisit capacity every quarter and before every planned event. It is far cheaper to add resources calmly than during an outage.
How IDX helps
IDX VPS plans come in several sizes for each stage of growth, and our dedicated servers are built to the processor, memory, storage and port speed you specify. Our NOC monitoring tracks resource use over time, and our team can review it with you and recommend the right size.
IDX on digital infrastructure
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