HA

High Availability

System design minimizing downtime -- typically via redundancy.

When you'd see it: System architecture and SLA discussions. "Is it HA?" asks whether a service survives a component failure without going down.

Why it matters: HA designs for minimal downtime by removing single points of failure, usually through redundancy and automatic failover. The more nines of uptime promised, the more HA engineering and cost it takes.

Common mistakes: Confusing HA (staying up through local failures) with DR (recovering from a disaster). HA avoids downtime. DR is how you come back after it.