# US 8,572,038 B2 · Systems and methods for performing data replication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,572,038 B2 - Document ID: US8572038B2 - Status: Granted - Kind: B2 - Application number: 13/118,182 - Filed: 2011-05-27 - Published: 2011-12-01 - Granted: 2013-10-29 - Earliest claimed: 2010-05-28 - Assignees: Commvault Systems, Inc. - Applicants: Andrei Erofeev - Inventors: Andrei Erofeev - Web page: https://patentgrep.com/patent/US8572038B2 ## CPC - G06F 16/1844: {Management specifically adapted to replicated file systems} - G06F 11/1435: {using file system or storage system metadata} - G06F 11/1471: involving logging of persistent data for recovery - G06F 11/1662: {the resynchronized component or unit being a persistent storage device (re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008)} - G06F 11/2094: {Redundant storage or storage space (G06F11/2056 takes precedence)} - G06F 16/1734: {Details of monitoring file system events, e.g. by the use of hooks, filter drivers, logs} - H04L 67/1095: Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes - G06F 11/1458: {Management of the backup or restore process} - G06F 2201/84: Using snapshots, i.e. a logical point-in-time copy of the data - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Preparing source data to be replicated in a continuous data replication environment. Certain systems and methods populate a file name database with entries having a unique file identifier descriptor (FID), short name and a FID of the parent directory of each directory or file on a source storage device. Such information is advantageously gathered during scanning of a live file system without requiring a snapshot of the source storage device. The database can be further used to generate absolute file names associated with data operations to be replayed on a destination storage device. Based on the obtained FIDs, certain embodiments can further combine write operations to be replayed on the destination storage device and/or avoid replicating temporary files to the destination system. ## Claims ### Claim 1 A method for performing data replication, the method comprising: monitoring with one or more processors of a source storage system a plurality of journal entries associated with writing data to a source storage device associated with the source storage system; identifying a first journal entry of the plurality of journal entries, the first journal entry comprising a first data write operation, a first file identifier descriptor (FID) of a file to be modified by the first data write operation on the source storage device, and a first location of a first portion of the file to be modified, wherein a FID identifies a file or directory of a file system on the source storage system and is usable to construct an absolute file name for transmitting data to a replication system; identifying a second journal entry of the plurality of journal entries, the second journal entry comprising a second data write operation, a second FID of a file to be modified by the second data write operation on the source storage device, and a second location of a second portion of the file to be modified, wherein the first journal entry and the second journal entry are from the same journal; determining with the one or more processors that the first and second data write operations can be combined into a single write operation based on a determination that the first and second FIDs both correspond to a first value; combining the first and second data write operations based on said determination; constructing with the one or more processors an absolute file name by associating the first value with a short name and at least one directory name, wherein neither the first nor second journal entries comprises the absolute file name; and transmitting the single write operation and the absolute file name to a destination storage device to replay on the destination storage device the data modifications associated with the first and second write operations, wherein the destination storage device stores a replicated version of data written to the source storage device. ### Claim 2 (depends on 1) The method of claim 1, wherein the first location comprises a first byte range and the second location comprises a second byte range. ### Claim 3 (depends on 2) The method of claim 2, wherein said determining that the first and second data write operations can be combined further comprises analyzing a distance between the first and second byte ranges. ### Claim 4 (depends on 3) The method of claim 3, wherein determining that the first and second data write operations can be combined further comprises determining that the distance is less than a threshold amount. ### Claim 5 (depends on 4) The method of claim 4, wherein the threshold amount is less than 1 KB. ### Claim 6 (depends on 5) The method of claim 5, wherein the threshold amount is approximately 200 bytes. ### Claim 7 (depends on 1) The method of claim 1, wherein said monitoring operations comprises processing the plurality of journal entries with a filter driver. ### Claim 8 (depends on 1) The method of claim 1, wherein said monitoring comprises analyzing a portion of the plurality of journal entries as received over a predetermined period of time. ### Claim 9 (depends on 8) The method of claim 8, additionally comprising adjusting the predetermined period of time based on a known good state of the source storage device data. ### Claim 10 (depends on 8) The method of claim 8, wherein said predetermined period of time is approximately four seconds. ### Claim 11 (depends on 1) The method of claim 1, additionally comprising: identifying multiple ones of the plurality of journal entries having other write operations that cannot be combined; reading byte ranges associated with the other write operations in order of increasing file offsets; and transmitting the other write operations to the destination storage device for replay on the destination storage device in the order of the increasing file offsets. ### Claim 12 A system for performing data replication, the system comprising: at least one computer application executing on a computing device and configured to generate operations associated with data on a source storage device associated with a source storage system; a filter module disposed between the at least one computer application and the source storage device, the filter module configured to: monitor a plurality of journal entries associated with writing data to the source storage device; identify a first journal entry of the plurality of journal entries, the first journal entry comprising a first data modification operation, a first file identifier descriptor (FID) of a file to be modified by the first data modification operation, and a first location of a first portion of the file to be modified, wherein a FID identifies a file or directory of a file system on the source storage system and is usable to construct an absolute file name for transmitting data to a replication system; identify a second journal entry of the plurality of journal entries, the second journal entry comprising a second data modification operation, a second FID of a file to be modified by the second data modification operation, and a second location of a second portion of the file to be modified, wherein the first journal entry and the second journal entry are from the same journal; a processing module configured to: determine that the first and second data modification operations can be combined into a single modification operation based on a determination that the first and second FIDs both correspond to a first value; and combine the first and second data modification operations based on said determination; and at least one database thread configured to construct an absolute file name for replaying the single modification operation on replication data of a destination storage device by associating the first value with a short name and at least one directory name, wherein neither the first nor second journal entries comprises the absolute file name, wherein the destination storage device stores a replicated version of data written to the source storage device. ### Claim 13 (depends on 12) The system of claim 12, wherein the filter module comprises a file system filter driver. ### Claim 14 (depends on 13) The system of claim 13, wherein the first data modification operation comprises a write operation, and wherein the file system filter driver is configured to obtain the first data modification operation and the first FID without receiving a copy of data to be written to the source storage device. ### Claim 15 (depends on 12) The system of claim 12, further comprising a database comprising file name data that associates each of the first and second FIDs with a short name and a parent FID. ### Claim 16 (depends on 12) The system of claim 12, wherein the first file location comprises an offset and a length of a byte range of the file to be modified. ### Claim 17 (depends on 12) The system of claim 12, further comprising a memory configured to store a portion of the operations generated over a predetermined period of time. ### Claim 18 (depends on 17) The system of claim 17, wherein the predetermined period of time is at least three seconds. ### Claim 19 A system for performing data replication, the system comprising: means for monitoring a plurality of journal entries associated with writing data to a source storage device associated with a source storage system; means for identifying a first journal entry of the plurality of journal entries, the first journal entry comprising a first data write operation, a first file identifier descriptor (FID) of a file to be modified on the source storage device, and a first location of a first portion of the file to be modified, and for identifying a second journal entry of the plurality of journal entries, the second journal entry comprising a second data write operation, a second FID of a file to be modified on the source storage device, and a second location of a second portion of the file to be modified, wherein a FID identifies a file or directory of a file system on the source storage system and is usable to construct an absolute file name for transmitting data to a replication system, and wherein the first journal entry and the second journal entry are from the same journal; means for determining that the first and second data write operations can be combined into a single write operation based on a determination that the first and second FIDs both correspond to a first value, and for combining the first and second data write operations based on said determination; means for constructing an absolute file name by associating the first value with a short name and at least one directory name, wherein neither the first nor second journal entries comprises the absolute file name; and means for transmitting the single write operation and the absolute file name to a destination storage device to replay on the destination storage device the data modifications associated with the first and second write operations, wherein the destination storage device stores a replicated version of data written to the source storage device. ### Claim 20 (depends on 19) The system of claim 19, further comprising means for storing file name data that associates each of the first and second FIDs with a short name and a parent FID usable to construct the absolute file name.