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CompTIA Server+ SK0-005 · Domain 2: Server administration

High availability: clustering (active-active vs active-passive), heartbeat, quorum, load balancing methods (round robin, least connections), failover and failback

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Last reviewed September 25, 2026 · Leer en español

High availability (HA) is designing a service so it keeps running, or recovers within seconds or minutes, when a component fails. Availability is often expressed as a percentage of uptime, such as 99.9 or 99.99 percent. The main tools are clusters and load balancers, and both rely on having no single point of failure.

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