Abstract: An apparatus to compare two datasets, each of which includes multiple data blocks, includes a comparison unit and a report generator. The comparison unit identifies block-level differences therebetween, by comparing block-level metadata between the first and second datasets, without comparing the contents of the data blocks. The report generator generates a human-readable report of the differences between the first and second version of the dataset, including the differences in individual data blocks between the first and second version of the dataset.

Abstract: A method and apparatus for backing up a computer system is disclosed. A backup is provided of a data stored on a first computer by the first computer generating a dump stream. The dump stream is transmitted to a second computer, the second computer uses the dump stream to maintain a file system copy of the data. One or more snapshots of the file system of the second computer are stored on a backup computer, the snapshots providing a backup of the data stored on the first computer.

Abstract: A system for transmitting replica data between a source system and a destination system provides various standalone headers and data following headers that identify aspects of the data stream in a generalized manner. On the destination storage system, a set of hidden metadata directories (“metadirs”) are provided for storing extended attributes in association with files on the destination. The system also supports a standalone header that instructs the destination to undo a backed-up changed file in the event that the source determines that the file was modified in the midst of a backup procedure and transmission to the destination.

Abstract: A system and method for managing a plurality of snapshots as provided. A set of metadata describing a file system is contained within the file system so that a snapshot of the file system includes the associated metadata. Backup client file systems are restored to a backup server using conventional dump and restore techniques. The backup server then utilizes a user-defined snapshot management schedule to manage the set of backups associated with the backup server. Such management of snapshots can include deletion of snapshots based upon a variety of parameters including the time stamp.

Abstract: A system and method for providing soft locks so applications can communicate their dependence upon PCPIs for a plurality of storage systems and applications. The soft locks, created and maintained by an application executing on one or more of the storage appliances, identify certain PCPIs that are to be retained by a storage appliance and its applications. An illustrative embodiment of this system and method is to use these soft locks to ensure that storage volume destinations along the cascaded chain of applications running on that or other storage systems retain the appropriate PCPI and state.

Abstract: A method and apparatus for operating a storage system is disclosed. A root node has a first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system. A persistent consistency point of the storage system is created at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data. A statutes indicator is set to indicate that an identified partial consistency point is completed. All partial consistency points are coalesced into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

Abstract: A system and method for managing data deduplication of a storage system utilizing persistent consistency point images (PCPIs). Once a target PCPI of a data transfer is generated, a backup management module of the storage system alerts a data deduplication module to begin deduplication of the data contained within the target PCPI. Once the deduplication procedure has been completed, the active file system of the storage system has been deduplicated, however, the target PCPI remains un-deduplicated. In response, the backup management module generates and exports a revised target PCPI. The previous target PCPI may then be deleted, thereby transitioning the exported PCPI's image of the state of the file system to a deduplicated state.

Abstract: A system and method for updating a replicated destination file system snapshot with changes in a source file system snapshot, facilitates construction of a new directory tree on the destination from source update information using a temporary or “purgatory” directory that allows any modified and deleted files on the destination active file system to be associated with (e.g. moved to) the purgatory directory if and until they are reused. In addition, an inode map is established on the destination that maps source inode numbers to destination inode numbers so as to facilitate building of the destination tree using inode/generation number tuples. The inode map allows resynchronization of the source file system to the destination. The inode map also allows association of two or more destination snapshots to each other based upon their respective maps with the source.

Abstract: A system and method for updating a replicated destination file system snapshot with changes in a source file system snapshot, facilitates construction of a new directory tree on the destination from source update information using a temporary or “purgatory” directory that allows any modified and deleted files on the destination active file system to be associated with (e.g. moved to) the purgatory directory if and until they are reused. In addition, an inode map is established on the destination that maps source inode numbers to destination inode numbers so as to facilitate building of the destination tree using inode/generation number tuples. The inode map allows resynchronization of the source file system to the destination. The inode map also allows association of two or more destination snapshots to each other based upon their respective maps with the source.

Abstract: A system and method for fault-tolerant synchronization of replica updates for fixed persistent consistency point image consumption. PCPIs are consumed at a fixed level and each coalesced PCPI presents a valid version of the source file system from some point in time. The qtrees concurrently move through a coalescing cycle wherein some qtrees are updated, some may update partially and some may not update at all. Partially updated qtrees are rolled-back to the previous state, after which all qtrees are transitioned to a stable state.

Abstract: In a system and method for updating a remote replicated destination file system snapshot with changes in a source file system snapshot, the snapshot being associated with a qtree (or other sub-organization of the file system volume), a qtree metadata file on the destination in provided. The qtree metadata file resides, in the destination volume, and outside the qtree structure. The metadata file stores state information with respect to each qtree. This metadata file resides at a known location in the destination volume. The metadata file can include a plurality of fixed length records having respective fields for storing various information including qtree-specific information, and can be part of a hidden metadata directory.

Abstract: A system and method for inserting checkpoints into a data stream and for restarting an asynchronous transmission of a data stream from a source file system to a destination file system is provided. The data stream can be a set of changes between a base snapshot and incremental snapshot of the source file system for update of a replicated file system on the destination. State information relating to the progress of the source in processing and transmitting the data stream is stored at regular intervals, and a checkpoint number associated with each stored segment of the state information is inserted into the data stream. The destination tracks the fall commitment of each segment of the data stream to persistent storage on the replicated file system. If an error or communication loss requires the data transfer to be restarted, the destination sends the checkpoint number associated with the last fully committed segment of the data stream.

Abstract: In a system and method for updating a remote replicated destination file system snapshot with changes in a source file system snapshot, users and processes are redirected to a local exported snapshot of the replicated snapshot on the active file system on the destination before beginning the next update of the active file system's replicated snapshot. In this manner, an unstable replicated snapshot is not accessed. Indirection is introduced into inode lookup at the destination as the destination's active file system is being updated. The indirection can be based upon a snapshot ID that conforms to a latest exported snapshot ID.

Abstract: A system and method for updating a replicated destination file system snapshot with changes in a source file system snapshot, provides an extensible, file system-independent format to transmit a data stream of change data over the network. The format enabled backward compatibility between different versions of applications running on the source and destination through use of discrete header types which, if not recognized by a version of the application are ignored. In addition, the headers, which can carry data, or act as basic headers for follow on data, include expansion space for additional information.

Abstract: A system and method for remote asynchronous replication or mirroring of changes in a source file system snapshot in a destination replica file system using a scan (via a scanner) of the blocks that make up two versions of a snapshot of the source file system, which identifies changed blocks in the respective snapshot files based upon differences in volume block numbers identified in a scan of the logical file block index of each snapshot. Trees of blocks associated with the files are traversed, bypassing unchanged pointers between versions and walking down to identify the changes in the hierarchy of the tree. These changes are transmitted to the destination mirror or replicated snapshot. This technique allows regular files, directories, inodes and any other hierarchical structure to be efficiently scanned to determine differences between versions thereof.

Abstract: A system and method for updating a replicated destination file system snapshot with changes in a source file system snapshot, facilitates construction of a new directory tree on the destination from source update information using a temporary or “purgatory” directory that allows any modified and deleted files on the destination active file system to be associated with (e.g. moved to) the purgatory directory if and until they are reused. In addition, an inode map is established on the destination that maps source inode numbers to destination inode numbers so as to facilitate building of the destination tree using inode/generation number tuples. The inode map allows resynchronization of the source file system to the destination. The inode map also allows association of two or more destination snapshots to each other based upon their respective maps with the source.

Abstract: In a system and method for updating a remote replicated destination file system snapshot with changes in a source file system snapshot, users and processes are redirected to a local exported snapshot of the replicated snapshot on the active file system on the destination before beginning the next update of the active file system's replicated snapshot. In this manner, an unstable replicated snapshot is not accessed. Indirection is introduced into inode lookup at the destination as the destination's active file system is being updated. The indirection can be based upon a snapshot ID that conforms to a latest exported snapshot ID.

Abstract: A system and method for updating a replicated destination file system snapshot with changes in a source file system snapshot, facilitates construction of a new directory tree on the destination from source update information using a temporary or “purgatory” directory that allows any modified and deleted files on the destination active file system to be associated with (e.g. moved to) the purgatory directory if and until they are reused. In addition, an inode map is established on the destination that maps source inode numbers to destination inode numbers so as to facilitate building of the destination tree using inode/generation number tuples. The inode map allows resynchronization of the source file system to the destination. The inode map also allows association of two or more destination snapshots to each other based upon their respective maps with the source.

Abstract: A system and method for managing a plurality of snapshots as provided. A set of metadata describing a file system is contained within the file system so that a snapshot of the file system includes the associated metadata. Backup client file systems are restored to a backup server using conventional dump and restore techniques. The backup server then utilizes a user-defined snapshot management schedule to manage the set of backups associated with the backup server. Such management of snapshots can include deletion of snapshots based upon a variety of parameters including the time stamp.

Abstract: A system and method for updating a replicated destination file system snapshot with changes in a source file system snapshot, provides an extensible, file system-independent format to transmit a data stream of change data over the network. The format enabled backward compatibility between different versions of applications running on the source and destination through use of discrete header types which, if not recognized by a version of the application are ignored. In addition, the headers, which can carry data, or act as basic headers for follow on data, include expansion space for additional information.