In a ship, bulkheads are partitions that, when sealed, divide the ship into separate, watertight compartments. With hatches closed, a bulkhead prevents water from moving from one section to another. In this way, a single penetration of the hull does not irrevocably sink the ship. The bulkhead enforces a principle of damage containment.

You can employ the same technique. By partitioning your systems, you can keep a failure in one part of the system from destroying everything. Physical redundancy is the most common form of bulkheads. If there are four independent servers, then a hardware failure in one can’t affect the others. Likewise, if there are two application instances running on a server and one crashes, the other will still ...

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