Patent application number | Description | Published |
20090006496 | Methods of determining and searching for modified blocks in a file system - The invention relates to a method of determining if a block was modified in a file system by comparing the versions of the base snapshot, the delta snapshot, and the space map block entry (b, e). In another aspect, the invention relates to a method of searching for blocks modified in a tree structured file system. The invention relates to methods and systems of snapshot management of a file system in a data storage system. To represent the snapshots, the invention maintains pointers to the root block pointer of each snapshot. When the active file system is modified, this invention avoids overwriting any blocks used by previous snapshots by allocating new blocks for the modified blocks. When the invention needs to put an established block in a new location, it must update a parent block to point to the new location. The update to the parent block may then require allocating a new block for the new parent block and so forth. Parts of the file system not modified since a snapshot remain in place. The amount of space required to represent snapshots scales with the fraction of the file system that users modify. To maintain snapshot integrity, this invention keeps track of the first and last snapshots that use each block in space map blocks spread throughout the file system data space. When users delete snapshots, this invention may use a background process to find blocks no longer used by any snapshot and makes them available for future use. | 01-01-2009 |
20100179959 | Systems and methods of searching for and determining modified blocks in a file system - The invention relates to a method of determining if a block was modified in a file system by comparing the versions of the base snapshot, the delta snapshot, and the space map block entry (b, e). In another aspect, the invention relates to a method of searching for blocks modified in a tree structured file system. The invention relates to methods and systems of snapshot management of a file system in a data storage system. To represent the snapshots, the invention maintains pointers to the root block pointer of each snapshot. When the active file system is modified, this invention avoids overwriting any blocks used by previous snapshots by allocating new blocks for the modified blocks. When the invention needs to put an established block in a new location, it must update a parent block to point to the new location. The update to the parent block may then require allocating a new block for the new parent block and so forth. Parts of the file system not modified since a snapshot remain in place. The amount of space required to represent snapshots scales with the fraction of the file system that users modify. To maintain snapshot integrity, this invention keeps track of the first and last snapshots that use each block in space map blocks spread throughout the file system data space. When users delete snapshots, this invention may use a background process to find blocks no longer used by any snapshot and makes them available for future use. | 07-15-2010 |
20120317079 | Systems and methods of data replication of a file system - The invention relates to methods for replicating a primary file system on a primary host to a secondary file system on a secondary host including determining a primary data block to replicate by reading a space map block entry (b, e) of the primary data block, wherein b represents the first snapshot and e the last snapshot to use the primary data block; computing a checksum of a primary data block and sending its number to the secondary host and determining a secondary data block that corresponds and computing its checksum then comparing the primary and secondary data block checksums and replicating the primary data block on the secondary file system when the primary and secondary checksums mismatch for the primary file system. In another aspect of the method if the primary and secondary checksums mismatch the method sends all data blocks from the primary file system allocated after a reliable snapshot on the secondary file system to the secondary host to be written on the secondary file system. | 12-13-2012 |
20130103644 | WRITABLE SNAPSHOTS - Embodiments of the invention include systems and methods for providing writable snapshot functionality for file systems. Pointer-based snapshots can be taken of an active version of the file system resulting in either (1) a read-only snapshot image and a new active version of the file system resulting from a read-only snapshot operation; or (2) a read-only snapshot image and two new active versions of the file system resulting from a writable snapshot operation. The two active file systems generated from writable snapshot operations are each independently and concurrently writable. Various techniques are also presented for handling multiple, concurrently active file systems. For example, novel techniques are described for allowing snapshot restore, compaction, and other functionality to operate in an environment having multiple read-only and writable versions of the file system. | 04-25-2013 |
20130110893 | METHODS OF PROCESSING FILES IN A MULTIPLE QUALITY OF SERVICE SYSTEM | 05-02-2013 |
20130325824 | OFFLINE VERIFICATION OF REPLICATED FILE SYSTEM - Embodiments of the invention include systems and methods for providing block-level verification of replicated file systems. Embodiments operate in context of data storage environments, which may typically have multiple file systems, snapshots of file systems, and replicas of file systems. In one illustrative scenario, a replica is created of a file system having multiple associated snapshots, and a user desires to verify the accuracy of the replica. A signature is created for each of the source active file system and the target replica file system, so that each signature includes records of both block-level signatures and block-level allocations. The signatures are compared to discover any differences. The differences may then be reconciled, where possible, to determine whether the differences indicate a corrupt or otherwise invalid replica. | 12-05-2013 |