التوافر والموثوقية بالقياس

في هذا الدرس

define availability and reliability with a measurement rule.

الموضوعات المخطط لها

• Availability: share of time (or requests) the service works; reliability: how long it works without failing and how correctly.
• 99.95% monthly is about 22 minutes of allowed downtime; verify the arithmetic for your window.
• Define "up": which endpoint, which probe, which errors count, which maintenance is excluded.
• Serial dependencies multiply: two 99.9% components in series give roughly 99.8%.
• Distinguish MTTR (recovery) from MTBF (failure interval); recovery speed is often cheaper to improve.