PARTIAL FILE RESTORE IN A DATA STORAGE SYSTEM
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Abstract
The data storage system according to certain aspects can implement partial file restore, where only a portion of the secondary copy of a file is restored. Such portion may be designated by one or more application offsets for the file. The system may provide an in-chunk index that includes mapping information between the application offsets and the secondary copy offsets. Chunks may refer to logical data units in which secondary copies are stored, and the in-chunk index for a chunk may be stored in secondary storage with the chunk. Because the mapping information may not be provided at a fixed interval, the system can search through application offsets in the in-chunk index to locate the secondary copy offset corresponding to the portion application offset(s). In this manner, the system may restore the designated portion of the secondary copy in a fast and efficient manner by using the in-chunk index.
8 Citations
40 Claims
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1-20. -20. (canceled)
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21. A method comprising:
using one or more computing devices comprising computer hardware; copying a first portion of a first file from primary storage to a buffer for writing to secondary storage, wherein data stored on the secondary storage is stored in one or more chunks, and wherein each chunk comprises a logical data unit for storing the data in the secondary storage in one or more secondary storage devices residing in the secondary storage; writing the first portion from the buffer to a location in a first chunk of the one or more chunks; creating a first entry in an index for the first chunk, the index stored in association with the first chunk, the first entry corresponding to the first portion of the first file and comprising; a first application offset corresponding to the first portion of the first file, and a first secondary storage offset indicating the location of the first portion of the first file within the first chunk in the secondary storage; and writing the first entry to the first chunk, wherein creation of the secondary copy involves a series of transactions in which data is written to the buffer and then written from the buffer to the secondary storage, and wherein an amount of data written to the buffer in each transaction is not predetermined. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A data storage system comprising:
one or more computing devices comprising computer hardware and configured to; copy a first portion of a first file from primary storage to a buffer for writing to secondary storage, wherein data stored on the secondary storage is stored in one or more chunks, and wherein each chunk comprises a logical data unit for storing the data in the secondary storage in one or more secondary storage devices residing in the secondary storage; write the first portion from the buffer to a location in a first chunk of the one or more chunks; create a first entry in an index for the first chunk, the index stored in association with the first chunk, the first entry corresponding to the first portion of the first file and comprising; a first application offset corresponding to the first portion of the first file; and a first secondary storage offset indicating the location of the first portion of the first file within the first chunk in the secondary storage; and write the first entry to the first chunk, wherein creation of the secondary copy involves a series of transactions in which data is written to the buffer and then written from the buffer to the secondary storage, and wherein an amount of data written to the buffer in each transaction is not predetermined. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40)
Specification