Restore accelerator for serial media backup systems
First Claim
1. A method of retrieving a desired backup file from a tape drive to a restore process, the method comprising the steps of:
- a) indexing, by an accelerator in a table, information about locations of backup files previously stored on tape volumes of a tape set;
b) obtaining, from a client, a name of the desired file to be retrieved from one or more respective tape volumes of the tape set;
c) sending, to the tape drive, a read message to read the desired file, the read message indicating that the tape volumes of the tape set are to be sequentially read for retrieval of the desired file;
d) intercepting, by the accelerator, the read message;
e) searching, by the accelerator in the table, using the obtained name of the desired backup file, for location information regarding the desired backup file stored on the tape set, the location information indicating the one or more respective tape volumes of the tape set where the desired file is stored and a number of files on each of the one or more respective tape volumes of the tape set to be skipped before the desired file;
f) sending, by the accelerator, one or more read commands to the tape drive to read the desired backup file from the one or more respective tape volumes using the location information;
g) sending, to the restore process by the accelerator, simulated file header record information stored in the table and associated with file header records to be skipped before the desired file; and
h) retrieving, by the restore process, the desired backup file after the restore process receives the simulated file header record information.
1 Assignment
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Accused Products
Abstract
A method for accelerating a tape backup system restore process receives a list of files that are to be restored and searches a tape catalogue to find tape volume and file sequence numbers for each file in the list of files, where the catalogue is an alphabetical listing of the contents of one or more backup tape volumes. The process appends the tape volume and file sequence numbers for each of the files to the list of files and then sorts the list of files according to tape volume and file sequence number. Accordingly, a list is obtained including the files that are to be restored, ordered according to the location of the files on the backup tape volumes. The restore process is accelerated by restoring files sequentially from this list and skipping over any intermediate files that are not on the list.
13 Citations
23 Claims
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1. A method of retrieving a desired backup file from a tape drive to a restore process, the method comprising the steps of:
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a) indexing, by an accelerator in a table, information about locations of backup files previously stored on tape volumes of a tape set; b) obtaining, from a client, a name of the desired file to be retrieved from one or more respective tape volumes of the tape set; c) sending, to the tape drive, a read message to read the desired file, the read message indicating that the tape volumes of the tape set are to be sequentially read for retrieval of the desired file; d) intercepting, by the accelerator, the read message; e) searching, by the accelerator in the table, using the obtained name of the desired backup file, for location information regarding the desired backup file stored on the tape set, the location information indicating the one or more respective tape volumes of the tape set where the desired file is stored and a number of files on each of the one or more respective tape volumes of the tape set to be skipped before the desired file; f) sending, by the accelerator, one or more read commands to the tape drive to read the desired backup file from the one or more respective tape volumes using the location information; g) sending, to the restore process by the accelerator, simulated file header record information stored in the table and associated with file header records to be skipped before the desired file; and h) retrieving, by the restore process, the desired backup file after the restore process receives the simulated file header record information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of file retrieval from a backup tape set including a plurality of tape volumes using an accelerator as an intermediate between a restore process and a tape drive, the method comprising the steps of:
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a) indexing, by the accelerator in a table, information indicating locations of backup files previously stored on the backup tape set; b) receiving an indication of one or more files that are to be retrieved; c) determining a location of each of the one or more files on the backup tape set; d) sending, by the restore process to the tape drive, a read message to read the one or more file from the tape set; e) intercepting, by the accelerator, the read message; f) searching, by the accelerator in the table, using obtained names of the desired files, for the location information regarding the one or more files on the backup tape set, the location information indicating, for each of the one or more files, a number of files on the backup tape set to be skipped before a respective desired file; g) sending, by the accelerator, one or more read commands to the tape drive to read each desired file by sequentially mounting and reading respective tapes of the tape set using the location information to skip the indicated number of files; and h) sending, to the restore process by the accelerator, simulated file header records stored in the table and associated with file header records to be skipped before the respective desired file; and i) retrieving, by the restore process, a sequence of the desired file header records interspersed with simulated file header records associated with file header records to be skipped. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A system for restoring backup data from a sequential data storage medium, the system comprising a general purpose computer and computer software for controlling the general purpose computer, the software including:
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a restore process for receiving requests, from a client, for retrieval of backup data from the sequential data storage medium, sending open and read commands to the data storage medium, receiving the backup data, and providing the backup data to the client; and a restore accelerator process for intercepting the open and read commands sent from the restore process to the data storage medium, gathering information in a table about locations of backup files previously stored on a tape set, searching in the table for location information regarding the desired backup files stored on the tape set, the location information indicating a number of files on the tape set to be skipped before each respective desired backup file, sending new open and read commands to the data storage medium to sequentially position the sequential data storage medium to respective locations of the backup data that are to be retrieved based on the location information in the table, retrieving the backup data from the data storage medium, while skipping intervening data that is not to be retrieved, modifying one or more file sequence numbers and checksum values of the backup data, and forwarding to the restore process the backup data including the modified one or more file sequence numbers, checksum values such that simulated file header records stored in the table and associated with file header records to be skipped are retrieved by the restore process in a sequence of the desired file header records interspersed with the simulated file header records associated with file header records to be skipped.
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23. A method of retrieving a desired backup file from a tape drive to a restore process, the method comprising the steps of:
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indexing, by an accelerator in a table, information about locations of backup files previously stored on a tape or a tape set; sending, to the tape drive, a read message to read the desired file; intercepting, by the accelerator, the read message; searching, by the accelerator in the table, using the obtained name of the desired backup file, for location information regarding the desired backup file stored on the tape or tape set, the location information indicating;
(1) a number of files on the tape to be skipped before the desired file or one or more respective tape volumes of the tape set where the desired files is stored and a (2) number of files on each of the one or more respective tape volumes of the tape set to be skipped before the desired file;sending, by the accelerator, one or more read commands to the tape drive to read the desired backup file using the location information; retrieving, by the restore process, the desired file header records and the simulated file header records stored in the table and associated with file header records to be skipped as an interspersed sequence; and altering, by the accelerator, file management information including simulated file header records to match the information about locations of the desired backup files previously stored on the tape or one or more volumes of the tape set.
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Specification