Abstract: The invention relates to a multiple QoS file system and methods of processing files at different QoS. The file system allocates VLUNs and using rules chooses an initial QoS for a file when created and moves files to different QoS using rules. Users see a single unified space of files, while administrators place files on storage according to file attributes. A file system enhances the descriptive information for each file to contain the chosen QoS for the file. The invention classifies volumes (e.g., file systems or LUNs) according to application requirements and allocates space for volumes. An IT administrator configures volumes specifying size, type and priority. The host schedules I/O requests in priority queues using the volume definition to match applications and reduce seek time between volumes of different priorities. The data storage system therefore places data on the performance band of a storage device that best supports needs.

Abstract: 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.

Abstract: 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.

Abstract: The present 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.

Abstract: The invention relates to a multiple QoS file system and methods of processing files at different QoS. The file system allocates VLUNs and using rules chooses an initial QoS for a file when created and moves files to different QoS using rules. Users see a single unified space of files, while administrators place files on storage according to file attributes. A file system enhances the descriptive information for each file to contain the chosen QoS for the file. The invention classifies volumes (e.g., file systems or LUNs) according to application requirements and allocates space for volumes. An IT administrator configures volumes specifying size, type and priority. The host schedules I/O requests in priority queues using the volume definition to match applications and reduce seek time between volumes of different priorities. The data storage system therefore places data on the performance band of a storage device that best supports needs.

Abstract: The invention relates to a multiple QoS file system and methods of processing files at different QoS according to rules. The invention allocates multiple VLUNs at different qualities of service to the multiQoS file system. Using the rules, the file system chooses an initial QoS for a file when created. Thereafter, the file system moves files to different QoS using rules. Users of the file system see a single unified space of files, while administrators place files on storage with the new cost and performance according to attributes of the files. A multiQoS file system enhances the descriptive information for each file to contain the chosen QoS for the file.

Abstract: The invention relates to a multiple QoS file system and methods of processing files at different QoS according to rules. The invention allocates multiple VLUNs at different qualities of service to the multiQoS file system. Using the rules, the file system chooses an initial QoS for a file when created. Thereafter, the file system moves files to different QoS using rules. Users of the file system see a single unified space of files, while administration place files on storage with the new cost and performance according to attributes of the files. A multiQoS file system enhances the descriptive information for each file to contain the chosen QoS for the file.

Abstract: The present 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.

Abstract: The present 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.