Slicing Up—and Iterating on—SLOs

Service Level Objectives (SLOs) should ideally focus on user experience, leading to a broader definition of "user" as anyone who interacts with the system being measured. This can result in overlapping responsibilities and multiple alerts for core components, which necessitates strategies like defining defensive patterns and reallocating responsibilities. Defensive patterns involve making reliable systems from unreliable parts by using strategies like redundancy and caching to enhance performance. Meanwhile, cutting up responsibility involves creating a tiered approach to SLOs, with high-level, end-to-end SLOs complemented by team-specific ones to manage individual response times and success rates. By understanding end-user expectations and annotating control boundaries within instrumentation, teams can better manage alerts and responsibilities, thereby protecting each other from unnecessary disruptions. Combining these approaches can optimize performance, with potential benefits like reduced processing times and improved error management, fostering a more systemic approach to reliability across an organization.