System and method for maintaining consistent points in file systems using a prime dependency list
First Claim
1. A computer-implemented method for maintaining a consistent point of a file system, the method comprising:
- receiving a request, by an archiver loaded in a memory and executed by a processor of a storage system having a plurality of storage units, to determine a consistent point of data stored in a file system of the storage system, wherein a first of the plurality of the storage units is an active storage unit that stores a first prime segment, and a second of the plurality of storage units is an archive storage unit that stores a second prime segment, wherein the first prime segment and the second prime segment collectively represent a first consistent view of the file system, wherein the first prime segment is a latest prime segment that was written to the active storage unit after the second prime segment was written to the archive storage unit;
in response to the request, retrieving by the processor, from the latest prime segment, a prime dependency list that includes information identifying all prime segments that collectively represent the first consistent view of the file system, the prime dependency list including information identifying the first prime segment stored in the active storage unit and information identifying the second prime segment stored in the archive storage unit, wherein the first and second prime segments are identified by a first prime segment identifier (ID) and a second prime segment ID, respectively, wherein the first and second prime segment IDs collectively identify a prime representing the first consistent view of the file system, wherein the active storage unit and the archive storage unit are separate physical storage units;
ascertaining, by the processor, each of the prime segments listed in the prime dependency list in an attempt to determine the consistent point of data, wherein the consistent point of data is a file system state which provides a valid view of the data at a point in time of the file system for restoration of the file system back to a prior known state, wherein the consistent point of data includes a first prime segment stored in the first storage unit and a second prime segment stored in the second storage unit, wherein the prime dependency list comprises a first entry and a second entry, wherein the first entry includes the first prime segment ID associated with a first storage unit ID that identifies the first storage unit, and wherein the second entry includes the second prime segment ID associated with a second storage unit ID that identifies the second storage unit, wherein the first storage unit stores a plurality of files that are backed up from a plurality of clients, wherein the second storage unit periodically archives at least a portion of the files by migrating the files from the first storage unit, while the first storage unit receives fresh backup data from the clients, and wherein the prime dependency list is used to identify the archived files stored in the second storage unit in order to identify all files corresponding to a particular consistent point of a file system stored both in the first storage unit and the second storage unit such that the first and the second portions of the consistent point of data do not need to reside on the same storage unit; and
restoring the file system back to a prior known state based on the identified first and second prime segments of the prime dependent list, including parsing the prime dependency list to determine storage units containing the first and second prime segments to retrieve the first and second prime segments.
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Accused Products
Abstract
According to one embodiment, a request is received for obtaining a consistent point of data stored in a file system of a storage system having a plurality of storage units. In response to the request, retrieving a prime dependency list from a first prime segment stored in a first of the storage units, where the prime dependency list includes information identifying at least a second prime segment stored in a second of the storage units. The first and second prime segments collectively form a prime segment representing a consistent view of the file system. Each of the prime segments listed in the prime dependency list is ascertained in an attempt to generate the consistent point of data.
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Citations
18 Claims
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1. A computer-implemented method for maintaining a consistent point of a file system, the method comprising:
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receiving a request, by an archiver loaded in a memory and executed by a processor of a storage system having a plurality of storage units, to determine a consistent point of data stored in a file system of the storage system, wherein a first of the plurality of the storage units is an active storage unit that stores a first prime segment, and a second of the plurality of storage units is an archive storage unit that stores a second prime segment, wherein the first prime segment and the second prime segment collectively represent a first consistent view of the file system, wherein the first prime segment is a latest prime segment that was written to the active storage unit after the second prime segment was written to the archive storage unit; in response to the request, retrieving by the processor, from the latest prime segment, a prime dependency list that includes information identifying all prime segments that collectively represent the first consistent view of the file system, the prime dependency list including information identifying the first prime segment stored in the active storage unit and information identifying the second prime segment stored in the archive storage unit, wherein the first and second prime segments are identified by a first prime segment identifier (ID) and a second prime segment ID, respectively, wherein the first and second prime segment IDs collectively identify a prime representing the first consistent view of the file system, wherein the active storage unit and the archive storage unit are separate physical storage units; ascertaining, by the processor, each of the prime segments listed in the prime dependency list in an attempt to determine the consistent point of data, wherein the consistent point of data is a file system state which provides a valid view of the data at a point in time of the file system for restoration of the file system back to a prior known state, wherein the consistent point of data includes a first prime segment stored in the first storage unit and a second prime segment stored in the second storage unit, wherein the prime dependency list comprises a first entry and a second entry, wherein the first entry includes the first prime segment ID associated with a first storage unit ID that identifies the first storage unit, and wherein the second entry includes the second prime segment ID associated with a second storage unit ID that identifies the second storage unit, wherein the first storage unit stores a plurality of files that are backed up from a plurality of clients, wherein the second storage unit periodically archives at least a portion of the files by migrating the files from the first storage unit, while the first storage unit receives fresh backup data from the clients, and wherein the prime dependency list is used to identify the archived files stored in the second storage unit in order to identify all files corresponding to a particular consistent point of a file system stored both in the first storage unit and the second storage unit such that the first and the second portions of the consistent point of data do not need to reside on the same storage unit; and restoring the file system back to a prior known state based on the identified first and second prime segments of the prime dependent list, including parsing the prime dependency list to determine storage units containing the first and second prime segments to retrieve the first and second prime segments. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A non-transitory computer-readable storage medium having instructions stored therein, which when executed by a computer, cause the computer to perform operations comprising:
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receiving a request, by an archiver loaded in a memory and executed by a processor of a storage system having a plurality of storage units, to determine a consistent point of data stored in a file system of the storage system, wherein a first of the plurality of the storage units is an active storage unit that stores a first prime segment, and a second of the plurality of storage units is an archive storage unit that stores a second prime segment, wherein the first prime segment and the second prime segment collectively represent a first consistent view of the file system, wherein the first prime segment is a latest prime segment that was written to the active storage unit after the second prime segment was written to the archive storage unit; in response to the request, retrieving by the processor, from the latest prime segment, a prime dependency list that includes information identifying all prime segments that collectively represent the first consistent view of the file system, the prime dependency list including information identifying the first prime segment stored in the active storage unit and information identifying the second prime segment stored in the archive storage unit, wherein the first and second prime segments are identified by a first prime segment identifier (ID) and a second prime segment ID, respectively, wherein the first and second prime segment IDs collectively identify a prime representing the first consistent view of the file system, wherein the active storage unit and the archive storage unit are separate physical storage units; ascertaining, by the processor, each of the prime segments listed in the prime dependency list in an attempt to determine the consistent point of data, wherein the consistent point of data is a file system state which provides a valid view of the data at a point in time of the file system for restoration of the file system back to a prior known state, wherein the consistent point of data includes a first prime segment stored in the first storage unit and a second prime segment stored in the second storage unit, wherein the prime dependency list comprises a first entry and a second entry, wherein the first entry includes the first prime segment ID associated with a first storage unit ID that identifies the first storage unit, and wherein the second entry includes the second prime segment ID associated with a second storage unit ID that identifies the second storage unit, wherein the first storage unit stores a plurality of files that are backed up from a plurality of clients, wherein the second storage unit periodically archives at least a portion of the files by migrating the files from the first storage unit, while the first storage unit receives fresh backup data from the clients, and wherein the prime dependency list is used to identify the archived files stored in the second storage unit in order to identify all files corresponding to a particular consistent point of a file system stored both in the first storage unit and the second storage unit such that the first and the second portions of the consistent point of data do not need to reside on the same storage unit; and restoring the file system back to a prior known state based on the identified first and second prime segments of the prime dependent list, including parsing the prime dependency list to determine storage units containing the first and second prime segments to retrieve the first and second prime segments. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A storage system, comprising:
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a processor; a memory; a plurality of storage units, wherein a first of the plurality of the storage units is an active storage unit that stores a first prime segment, and a second of the plurality of storage units is an archive storage unit that stores a second prime segment, wherein the first prime segment and the second prime segment collectively represent a first consistent view of the file system, wherein the first prime segment is a latest prime segment that was written to the active storage unit after the second prime segment was written to the archive storage unit; and an archiver loaded in the memory and executed by the processor to in response to a request for obtaining a consistent point of data stored in a file system, retrieve, from the latest prime segment, a prime dependency list that includes information identifying all prime segments that collectively represent the first consistent view of the file system, the prime dependency list including information identifying the first prime segment stored in the active storage unit and information identifying the second prime segment stored in the archive storage unit, wherein the first and second prime segments are identified by a first prime segment identifier (ID) and a second prime segment ID, respectively, wherein the first and second prime segment IDs collectively identify a prime representing the first consistent view of the file system, wherein the active storage unit and the archive storage unit are separate physical storage units, ascertain each of the prime segments listed in the prime dependency list in an attempt to determine the consistent point of data, wherein the consistent point of data is a file system state which provides a valid view of the data at a point in time of the file system for restoration of the file system back to a prior known state, wherein the consistent point of data includes a first prime segment stored in the first storage unit and a second prime segment stored in the second storage unit, wherein the prime dependency list comprises a first entry and a second entry, wherein the first entry includes the first prime segment ID associated with a first storage unit ID that identifies the first storage unit, and wherein the second entry includes the second prime segment ID associated with a second storage unit ID that identifies the second storage unit, wherein the first storage unit stores a plurality of files that are backed up from a plurality of clients, wherein the second storage unit periodically archives at least a portion of the files by migrating the files from the first storage unit, while the first storage unit receives fresh backup data from the clients, and wherein the prime dependency list is used to identify the archived files stored in the second storage unit in order to identify all files corresponding to a particular consistent point of a file system stored both in the first storage unit and the second storage unit such that the first and the second portions of the consistent point of data do not need to reside on the same storage unit, and restoring the file system back to a prior known state based on the identified first and second prime segments of the prime dependent list, including parsing the prime dependency list to determine storage units containing the first and second prime segments to retrieve the first and second prime segments. - View Dependent Claims (16, 17, 18)
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Specification