Abstract: Methods and apparatus for a continuous data protection system including replication and journaling, to detect a first problem, react to the first problem, recover from the first problem, determine whether to enter a regulation state due to repetition of the first problem, enter the regulation state, and maintain the regulation state after detecting the first problem again.

Abstract: A method for incremental compaction, including selecting a first section from a plurality of sections in a memory, and identifying references to elements in the first section. While identifying, selecting a sub-area of the first section and continuing the identifying while identifying only those references to elements in the sub-area. The method further includes holding in a data structure the identified references to elements in the first section, and if the data structure overflows, deleting from the data structure the reference elements not in the sub-area. The identifying is continued while holding in the data structure only those references to elements in the sub-area. Selecting, identifying and continuing may be performed by a plurality of threads performing the steps in parallel.