The Advent of Monitoring, Day 8: How to Monitor All the Nines of Your Service-Level Agreements
If you have large(r) customers, there is a point where they ask you for service-level agreements, or short SLAs. These are customer contracts defining different aspects of your service and what you guarantee for them. One common agreement is around availability, or, colloquially speaking, uptime. Your contract might state, and I am not a lawyer, that you guarantee that your service (or core parts of it) is available 99.99% of the time of a given period, mostly per month, quarter, or year.