Abstract: A method and system for emulating tape library commands is disclosed. Tape library commands implemented in response to commands received from a data protection application are emulated in a disk based storage medium so that existing data protection applications may be used to copy data to and from the disk based storage medium.

Abstract: A system for synchronizing a secondary volume with a primary volume in a continuous data protection system includes scanning means for scanning a region of the primary volume; comparing means for comparing the scanned region with a corresponding region of the secondary volume; storing means for storing an identification of the scanned region in a compare delta map when the comparing means returns a discrepancy between the scanned region and the corresponding region; copying means for copying data from the primary volume to the secondary volume, using the compare delta map as a guide to locate the data to copy; and revising means for revising the compare delta map by removing any changes made to the primary volume during a scan interval, which is a period of time required to scan the primary volume.

Abstract: A method and apparatus for managing backup data is disclosed. A data backup system defines a plurality of time windows for creating and maintaining backup data in accordance with a data backup policy. Each of the time windows is assigned a predetermined amount of storage space. When the data backup system creates backup data, the system determines whether a storage space assigned to a time window is large enough to accommodate new backup data. If the storage space is large enough, the new backup data is stored. However, if the storage space is not large enough, the system deletes the oldest backup data until enough storage space is obtained.

Abstract: A method for tracking changes on a primary volume in a continuous data protection system writes data to the primary volume. A copy of the data is written to a secondary volume, the secondary volume including all writes made to the primary volume. Each write made to the secondary volume is mapped in a data structure, such that the data structure tracks changes on the primary volume between two different points in time.

Abstract: A method for browsing objects on a protected volume in a continuous data protection system begins by displaying a list of top-level objects to a user who selects a top-level object to browse. A snapshot is selected from the selected top-level object and is decoded. A list of objects in the selected snapshot is displayed and the user selects an object to browse. The selected object is decoded and operations are performed on the selected object. The user can browse the protected volume by snapshots in the top-level object or by a range of time of coverage of the top-level object.

Abstract: The invention is a method and system for copying backup data to a virtual tape library (VTL), where data written to the VTL can optionally be stored on removable disk media for offsite storage. The invention minimizes dependency on tape media without taxing the resources of any of the servers and without the need for the data protection application (DPA) to perform a second backup pass. Backup data written to the VTL can optionally be copied to the VTL's default storage area and/or to a predetermined set of disks that may be removed and stored offsite.

Abstract: A method and apparatus for efficiently deleting data including backup or snapshots upon expiration are disclosed. The data can be deleted even without physical access to the data. A data generation unit generates a data. Each data has an expiration time and should be deleted upon expiration. An encryption unit encrypts the data, and the encrypted data is stored in data storage. A controller monitors whether there is an expired data, and if there is an expired data, the controller deletes a key necessary for decrypting the expired data.

Abstract: A method and system for generating a snapshot in a consistent state is disclosed. The system comprises a host computer, a primary data storage, a data protection unit, and a secondary data storage. The data protection unit monitors a state of an application which is running on the host computer. The data protection unit generates a snapshot of data stored in a primary data storage when the application is in a consistent state, and stores the snapshot on a secondary storage. In the event of a system failure, the data is recovered using the last snapshot.

Abstract: The present invention is a tape library comprising both a small front-end portion and a larger back-end portion. The front-end portion is a visible virtual or physical tape library; and the back-end portion is a large invisible virtual or physical tape vault. The DPA is a typical DPA which only sees the front-end library. If desired, all messages regarding the importing and exporting of tapes are reviewed by an agent. The agent manages the automatic transfer of tapes between the front-end and the back-end, and notifies the user when a manual import or export is needed. This greatly reduces both the amount of hardware required to establish a virtual or physical tape library and also reduces the amount of labor required by a user to physically import and export tapes. If both the front-end library and the back-end vault are virtual and reside on the same virtual tape library appliance, no data movement is necessary and the tapes can be moved merely by performing small software state changes.

Abstract: A method of protecting a data storage system including the steps of: providing a disk system including a plurality of disk modules, each disk module containing a disk controller and a disk driver, the disk driver being in detachable electrical communication with the disk controller; and physically disconnecting the disk controller from the disk driver for any of the plurality of disk modules that are not required by the data storage system for the transfer of data.

Abstract: A method and system for efficiently storing and transferring data in a virtual tape library environment is disclosed. Data is written to a virtual tape library that emulates a physical tape library. Data stored in the virtual tape library may be compressed and an estimated compression ratio may be dynamically computed. While data is written to the virtual tape library, an end-of-tape signal is provided based on the estimated compression ratio.

Abstract: A method and system wherein a plurality of different file system views may be provided for the same data. Data copied in a sequential format to a disk based repository using a data protection application is decoded so that the data may be presented and accessed using a standard file system view. The standard file system may be used to randomly access the data as desired.

Abstract: A method for synchronizing a secondary volume with a primary volume in a continuous data protection system begins by scanning a region of the primary volume, which is then compared with a corresponding region of the secondary volume. An identification of the scanned region is stored in a compare delta map when the comparison results in a discrepancy between the scanned region and the corresponding region. Data is copied from the primary volume to the secondary volume, using the compare delta map as a guide to locate the data to copy. If the data protection system has failed just prior to the restore process being initiated, it is termed a re-baseline, and the entire primary volume is scanned. If the data protection system is active prior to the restore process being initiated, it is termed a re-synchronization, and is optimized by scanning only select regions of the primary volume.

Abstract: A method and system where data is maintained in a continuous data protection system is disclosed. A primary volume may be protected according to an any-point-in-time (APIT) window wherein restores may be performed at any time as desired. The APIT window may be of any time duration as desired. Outside of the APIT window, a retention policy for phasing out data may be established as desired.

Abstract: A system for synchronizing a secondary volume with a primary volume in a continuous data protection system includes scanning means for scanning a region of the primary volume; comparing means for comparing the scanned region with a corresponding region of the secondary volume; storing means for storing an identification of the scanned region in a compare delta map when the comparing means returns a discrepancy between the scanned region and the corresponding region; copying means for copying data from the primary volume to the secondary volume, using the compare delta map as a guide to locate the data to copy; and revising means for revising the compare delta map by removing any changes made to the primary volume during a scan interval, which is a period of time required to scan the primary volume.

Abstract: In a continuous data protection system having a primary volume and a secondary volume, a method for data recovery begins by selecting a snapshot of the primary volume to be recovered and a location on which the snapshot is to be loaded. A point in time (PIT) map is created for the selected snapshot, and the selected snapshot is loaded at the selected location. A data block from the PIT map is resolved to determine which block on the secondary volume is presented as being part of the snapshot. The snapshot is accessed via a host computer as if the snapshot was the primary volume at an earlier point in time, corresponding to the time of the selected snapshot.

Abstract: A method and system wherein data is structured so that writes may be continuously duplicated and a protected volume may be restored to a particular point in time as desired. Writes are continuously duplicated on a secondary volume and organized into delta maps. The delta maps indicate which memory blocks were written to during a particular time frame.

Abstract: A method and apparatus for efficiently deleting data including backup or snapshots upon expiration are disclosed. The data can be deleted even without physical access to the data. A data generation unit generates a data. Each data has an expiration time and should be deleted upon expiration. An encryption unit encrypts the data, and the encrypted data is stored in data storage. A controller monitors whether there is an expired data, and if there is an expired data, the controller deletes a key necessary for decrypting the expired data.

Abstract: A method and system for copying backup data is disclosed. Backup data may be copied to a first virtual tape library in the same format as it would be copied to a physical tape library. The backup data may also be electronically copied to a second virtual tape library or to a physical tape library.

Abstract: The present invention is a tape library comprising both a small front-end portion and a larger back-end portion. The front-end portion is a visible virtual or physical tape library; and the back-end portion is a large invisible virtual or physical tape vault. The DPA is a typical DPA which only sees the front-end library. If desired, all messages regarding the importing and exporting of tapes are reviewed by an agent. The agent manages the automatic transfer of tapes between the front-end and the back-end, and notifies the user when a manual import or export is needed. This greatly reduces both the amount of hardware required to establish a virtual or physical tape library and also reduces the amount of labor required by a user to physically import and export tapes. If both the front-end library and the back-end vault are virtual and reside on the same virtual tape library appliance, no data movement is necessary and the tapes can be moved merely by performing small software state changes.