Uptime is the percentage of time a system or service is available and working.
Why it matters:
- Critical for businesses that rely on online systems or services.
- Even small amounts of downtime can cost thousands in lost productivity or revenue.
- Often used in SLAs (e.g., 99.9% uptime = ~8 hours of downtime per year).
Pro tip: “Five nines” (99.999%) uptime is the gold standard — but it requires significant investment in redundancy.
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