99.999% uptime — five nines.
99.999% uptime allows just over 5 minutes of downtime per year. That's less than a second per day. At this level, even a brief DNS propagation delay or a slow health check can consume your budget. Five nines is a goal that very few systems actually achieve, and even fewer sustain.
Maximum allowed downtime
Per day
0.86s
Per week
6s
Per month
26s
Per year
5m 15s
WHO NEEDS IT
Who targets 99.999%
Core cloud infrastructure (DNS, CDN, identity providers), financial trading systems, emergency services, telecommunications. Systems where even seconds of downtime have outsized consequences.
WHAT IT TAKES
How to achieve five nines
Multi-region active-active deployments, automated remediation (not just alerting — actual self-healing), chaos engineering, redundancy at every layer including the monitoring itself, and an operational maturity that most organizations frankly don't have. If you're targeting five nines, you probably have a dedicated reliability team.
Other uptime tiers
Measure your actual uptime.
Larm uses multi-probe voting to verify outages before alerting — so false positives don't eat into your uptime budget.