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“Two examples illustrate the redundancy principle. First, when a virtual machine fails in a cloud-based system, an identical instance is started automatically. Second, a critically important system should have at least one secondary backup system that runs in parallel with the primary system to ensure a safe fallback. Leading up to the next principle, we note that the secondary system should differ from the primary system to avoid both failing for the same reasons.” — Kjell Jorgen Hole
Two examples illustrate the redundancy principle. First, when a virtual machine fails in a cloud-based system, an identical instance is started automatically. Second, a critically important system should have at least one secondary backup system that runs in parallel with the primary system to ensure a safe fallback. Leading up to the next principle, we note that the secondary system should differ from the primary system to avoid both failing for the same reasons.