Downtime
ELI5 — The Vibe Check
Downtime is when your app is broken and users can't access it. It costs money, damages reputation, and makes everyone's phone buzz with alerts. The goal of DevOps is to keep downtime as close to zero as possible through redundancy, health checks, and fast rollbacks.
Real Talk
Downtime refers to periods when a system is unavailable or not functioning correctly. It can be planned (maintenance windows) or unplanned (incidents). Teams calculate downtime to measure SLA compliance, and use techniques like blue-green deployments and circuit breakers to minimize unplanned downtime.
When You'll Hear This
"We had 45 minutes of downtime last night — the post-mortem is at 2pm." / "Zero downtime deployment means users never see an outage during releases."
Related Terms
Blue-Green Deployment
Blue-green deployment means running two identical production environments — Blue (current) and Green (new).
Incident
An incident is when something has gone wrong in production and users are affected.
Rollback
A rollback is the panic button. When you deploy something and it breaks production, you hit rollback and the system reverts to the last working version — l...
SLA (Service Level Agreement)
An SLA is a contract between you and your users about how reliable your service will be. 'We promise the app will be up 99.9% of the time.
Uptime
Uptime is how long your service has been up and working without going down. It's usually expressed as a percentage like 99.9%. 'Three nines' (99.
Zero Downtime Deployment
Old-school deploys meant 5 minutes of downtime while the server restarted. Users got a 503 and emailed you.