Method and system for mirroring and archiving mass storage
First Claim
1. In a primary system that has a primary mass storage and is in communication with a secondary system that has a secondary mass storage, a method for mirroring and archiving the primary mass storage on the secondary mass storage, the method comprising:
- after the secondary mass storage has been synchronized with the primary mass storage, tracking changes to the primary mass storage during a time interval;
identifying an end of the time interval by identifying when the primary mass storage is in a logically consistent state;
using the tracked changes to create an update that includes any tracked changes necessary to represent the state of the primary mass storage at the end of the time interval; and
transferring the update to the secondary mass storage, such that the secondary mass storage can be brought current with the logically consistent state of the primary mass storage.
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Accused Products
Abstract
A method and system for mirroring and archiving mass storage. A primary mass storage and a secondary mass storage are synchronized to contain the same data. Thereafter, a primary system tracks changes made to the primary mass storage. These changes are consolidated periodically into update files, the consolidations representing changes made to the primary mass storage during a time interval that ends when the primary mass storage is in a logically consistent state. These update files contain only those changes necessary to represent the modified state of the primary mass storage at the time of the update. The primary system then transfers the update files to a secondary system to bring the secondary mass storage current with the primary mass storage. The consolidation minimizes the amount of information that must be transferred and therefore allows for a relatively low band width communication channel. In addition, update files may be cached by the primary system so that requests for mirrored or archived data may be fulfilled by the primary system cache rather than requiring access to the secondary system.
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Citations
22 Claims
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1. In a primary system that has a primary mass storage and is in communication with a secondary system that has a secondary mass storage, a method for mirroring and archiving the primary mass storage on the secondary mass storage, the method comprising:
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after the secondary mass storage has been synchronized with the primary mass storage, tracking changes to the primary mass storage during a time interval;
identifying an end of the time interval by identifying when the primary mass storage is in a logically consistent state;
using the tracked changes to create an update that includes any tracked changes necessary to represent the state of the primary mass storage at the end of the time interval; and
transferring the update to the secondary mass storage, such that the secondary mass storage can be brought current with the logically consistent state of the primary mass storage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computer program product for implementing, in a primary system that has a primary mass storage and is in communication with a secondary system that has a secondary mass storage, a method for mirroring and archiving the primary mass storage on the secondary mass storage, the computer program product comprising:
a computer-readable medium carrying computer-executable instructions for implementing the method, the computer-executable instructions, when executed, causing the primary system to;
track changes to the primary mass storage during a time interval that occurs after the secondary mass storage has been synchronized with the primary mass storage;
identify an end of the time interval by identifying when the primary mass storage is in a logically consistent state;
use the tracked changes to create an update that includes any tracked changes necessary to represent the state of the primary mass storage at the end of the time interval; and
transfer the update to the secondary mass storage, such that the secondary mass storage can be brought current with the logically consistent state of the primary mass storage. - View Dependent Claims (14, 15, 17, 18, 19, 20)
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16. The computer program product of claim 16, wherein the update does not include tracked changes that represent an intermediate state of the primary mass storage that existed after a beginning and before the end of the time interval.
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21. In a primary system that has a primary mass storage and is in communication with a secondary system having a secondary mass storage, a method for mirroring and archiving the primary mass storage by transmitting to the secondary mass storage only those changes to the primary mass storage that are necessary to bring the secondary mass storage current with the primary mass storage, while representing a plurality of logically consistent states of the primary mass storage, the method comprising:
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initiating synchronization of the secondary mass storage with the primary mass storage; and
for each of a plurality of distinct time intervals;
changing data stored in storage locations of the primary mass storage;
identifying when the primary mass storage is in a logically consistent state, so as to identify an end of a current time interval of the plurality of distinct time intervals;
as the data is changed, storing information representing all changes that have been made in the storage locations during the each of the plurality of time intervals in updates that correspond to the plurality of time intervals;
consolidating the stored information in each update such that each update includes only the changes that are required for bringing the secondary mass storage device current with the primary mass storage device as the data in the primary mass storage device exists at the end of the corresponding time interval; and
transferring each update to the secondary mass storage, such that the secondary mass storage can be brought current with the logically consistent states of the primary mass storage corresponding to the updates. - View Dependent Claims (22)
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Specification