Abstract: Various methods and systems for using adaptive data compression in a backup system are disclosed. One method involves detecting whether to compress a unit of storage that is to be backed up. The detecting involves attempting to compress a portion of the unit of storage. If the attempt to compress the portion of the unit of storage meets a specified compression performance threshold, i.e., if the unit of storage is compressible, the unit of storage is compressed. Otherwise the unit of storage is not compressed.

Abstract: Analyzing backup objects maintained by a de-duplication server. A plurality of first objects may be maintained. Each first object may refer to second object(s) and each second object may refer back to at least one first object. For each respective first object, the respective first object may be analyzed to determine the one or more second objects referred to by the respective first object. Correspondingly, a command may be generated for each respective second object of the determined second object(s), thereby generating a plurality of commands. Each command may be used to verify that the respective second object refers back to the respective first object. The plurality of commands may be sorted into a disk access order. The commands may be used to verify that each second object refers back to first objects that refer to the second object.

Abstract: Analyzing backup objects maintained by a de-duplication server. A plurality of first objects may be maintained. Each first object may refer to second object(s) and each second object may refer back to at least one first object. For each respective first object, the respective first object may be analyzed to determine the one or more second objects referred to by the respective first object. Correspondingly, a command may be generated for each respective second object of the determined second object(s), thereby generating a plurality of commands. Each command may be used to verify that the respective second object refers back to the respective first object. The plurality of commands may be sorted into a disk access order. The commands may be used to verify that each second object refers back to first objects that refer to the second object.

Abstract: There can be provided a system, method and apparatus to enable a data object to be removed from a single-instancing data object store in such a way as to ensure that only data objects to which all references have been removed are actually removed from the store. Thereby, consistency and reliability of storage can be maintained while allowing a data object which genuinely needs to be deleted to be removed from the store.