A method and apparatus for managing spare partition units in a partitionable computing device is disclosed. The method comprises detecting if a spare partition unit is required for addition or replacement in a local operating system and if a spare partition unit is required for addition, initiating an addition of a spare partition unit. If a spare partition unit is required for replacement, a replacement of a failing partition unit with a spare partition unit is initiated; part of the memory of the failing partition unit is passively migrated into the memory of the spare partition unit's partition; part of the memory of the failing partition unit is also actively migrated into the memory of the spare partition unit's partition; and the partitionable computing device is cleaned up. Partition units are replaced without requiring that computer-executable instructions be recompiled.