Managing cache data and metadata
First Claim
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1. A computer system, comprising:
- a memory;
a storage medium storing a plurality of data items at respective addresses;
a cache device also storing the plurality of data items at corresponding addresses and cache metadata providing a mapping between the address on the storage medium and the corresponding address on the cache device at which each data item is stored, the cache metadata being stored in a hierarchical data structure comprising a plurality of hierarchy levels;
at least one processor programmed to;
store cache metadata on the cache device in response to a command to shut down or reboot the computer;
upon initiating a reboot of the computer, load only a subset of the plurality of hierarchy levels to the memory; and
verify that a first data item of the plurality of data items was not modified after storage of the first data item in the cache device.
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Abstract
Embodiments of the invention provide techniques for managing cache metadata providing a mapping between addresses on a storage medium (e.g., disk storage) and corresponding addresses on a cache device at which data items are stored. In some embodiments, cache metadata may be stored in a hierarchical data structure comprising a plurality of hierarchy levels. When a reboot of the computer is initiated, only a subset of the plurality of hierarchy levels may be loaded to memory, thereby expediting the process of restoring the cache metadata and thus startup operations. Startup may be further expedited by using cache metadata to perform operations associated with reboot.
315 Citations
17 Claims
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1. A computer system, comprising:
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a memory; a storage medium storing a plurality of data items at respective addresses; a cache device also storing the plurality of data items at corresponding addresses and cache metadata providing a mapping between the address on the storage medium and the corresponding address on the cache device at which each data item is stored, the cache metadata being stored in a hierarchical data structure comprising a plurality of hierarchy levels; at least one processor programmed to; store cache metadata on the cache device in response to a command to shut down or reboot the computer; upon initiating a reboot of the computer, load only a subset of the plurality of hierarchy levels to the memory; and verify that a first data item of the plurality of data items was not modified after storage of the first data item in the cache device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for use in a computer system comprising a memory, a storage medium storing a plurality of data items at respective addresses, and a cache device also storing the plurality of data items at corresponding addresses and cache metadata providing a mapping between the address on the storage medium and the corresponding address on the cache device at which each data item is stored, the cache metadata being stored in a hierarchical data structure comprising a plurality of hierarchy levels, the method comprising acts of:
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storing cache metadata on the cache device in response to a command to shut down or reboot the computer; upon initiating a reboot of the computer system, loading only a subset of the plurality of hierarchy levels to the memory; and verifying that a first data item of the plurality of data items was not modified after storage of the first data item in the cache device.
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17. At least one recording medium storing instructions encoded thereon that, when executed by a computer system comprising a memory, a storage medium storing a plurality of data items at respective addresses, and a cache device also storing the plurality of data items at corresponding addresses and cache metadata providing a mapping between the respective address on the storage medium and the corresponding address on the cache device at which each data item is stored, the cache metadata being stored in a hierarchical data structure comprising a plurality of hierarchy levels, cause the computer system to perform a method comprising acts of:
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storing cache metadata on the cache device in response to a command to shut down or reboot the computer; upon initiating a reboot of the computer system, loading only a subset of the plurality of hierarchy levels to the memory; and verifying that a first data item of the plurality of data items was not modified after storage of the first data item in the cache device.
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Specification