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SRE Best Practices for Capacity Management

Doug Colish
login Usenix Mag., vol. 45(4) (2020)


As an SRE, you're responsible for determining the initial resource requirements of your service and ensuring your service behaves reasonably even in the face of unexpected demand. Capacity management is the process of ensuring you have the appropriate amount of resources for your service to be scalable, efficient, and reliable. User-facing and company internal services must accommodate both expected and unexpected growth. We define utilization as the percentage of a resource that is being used. It's difficult to determine initial resource utilization and predict future needs. We present ways to estimate utilization and identify blind spots, and we discuss the benefits of building in redundancy to avoid failures. You'll use this information to design your architecture such that increasing the resource allocation for each component of the service effectively increases the capacity of the entire service linearly.