摘要:
A method and apparatus for managing the caching of data on an auxiliary memory of a computer. Pages of data may be cached on an auxiliary memory, such as a flash memory, at a virtual level using an identifier that does not involve a physical address of the pages on a memory. Pages may be cached on auxiliary memory that may be removable from the computer, e.g., by unplugging the memory from the computer. Page data may be encrypted and/or compressed on the auxiliary memory. An authentication indicator may be used to verify the accuracy of cached data in the case of an interrupted connection to the auxiliary memory, e.g., as a result of computer power down, hibernation, removal of the memory from the computer, etc.
摘要:
A method and apparatus for managing the caching of data on an auxiliary memory of a computer. Pages of data may be cached on an auxiliary memory, such as a flash memory, at a virtual level using an identifier that does not involve a physical address of the pages on a memory. Pages may be cached on auxiliary memory that may be removable from the computer, e.g., by unplugging the memory from the computer. Page data may be encrypted and/or compressed on the auxiliary memory. An authentication indicator may be used to verify the accuracy of cached data in the case of an interrupted connection to the auxiliary memory, e.g., as a result of computer power down, hibernation, removal of the memory from the computer, etc.
摘要:
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 data items are stored. In some embodiments, cache metadata may be stored in a hierarchical data structure comprising a plurality of hierarchy levels. Only a subset of the plurality of hierarchy levels may be loaded to memory, thereby reducing the memory “footprint” of cache metadata and expediting the process of restoring the cache metadata during startup operations. Startup may be further expedited by using cache metadata to perform operations associated with reboot. Thereafter, as requests to read data items on the storage medium are processed using cache metadata to identify addresses at which the data items are stored in cache, the identified addresses may be stored in memory. When the computer is later shut down, instead of having to transfer the entirety of the cache metadata from memory to storage, only the subset of the plurality of hierarchy levels and/or the identified addresses previously loaded to memory may be transferred (e.g., to the cache device), thereby expediting the shutdown of the computer.
摘要:
Embodiments of the invention provide techniques for ensuring that the contents of a non-volatile memory device may be relied upon as accurately reflecting data stored on disk storage across a power transition such as a reboot. For example, some embodiments of the invention provide techniques for determining whether the cache contents and/or or disk contents are modified during a power transition, causing cache contents to no longer accurately reflect data stored in disk storage. Further, some embodiments provide techniques for managing cache metadata during normal (“steady state”) operations and across power transitions, ensuring that cache metadata may be efficiently accessed and reliably saved and restored across power transitions.
摘要:
To ensure that the contents of a non-volatile memory device cache may be relied upon as accurately reflecting data stored on disk storage, it may be determined whether the cache contents and/or disk contents are modified during a power transition, causing cache contents to no longer accurately reflect data stored in disk storage. The cache device may be removable from the computer, and unexpected removal of the cache device may cause cache contents to no longer accurately reflect data stored in disk storage. Cache metadata may be managed during normal operations and across power transitions, ensuring that cache metadata may be efficiently accessed and reliably saved and restored across power transitions. A state of a log used by a file system may be determined prior to and subsequent to reboot of an operating system in order to determine whether data stored on a cache device may be reliably used.
摘要:
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.
摘要:
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 data items are stored. In some embodiments, cache metadata may be stored in a hierarchical data structure comprising a plurality of hierarchy levels. Only a subset of the plurality of hierarchy levels may be loaded to memory, thereby reducing the memory “footprint” of cache metadata and expediting the process of restoring the cache metadata during startup operations. Startup may be further expedited by using cache metadata to perform operations associated with reboot. Thereafter, as requests to read data items on the storage medium are processed using cache metadata to identify addresses at which the data items are stored in cache, the identified addresses may be stored in memory. When the computer is later shut down, instead of having to transfer the entirety of the cache metadata from memory to storage, only the subset of the plurality of hierarchy levels and/or the identified addresses previously loaded to memory may be transferred (e.g., to the cache device), thereby expediting the shutdown of the computer.
摘要:
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 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. Thereafter, as requests to read data items on the storage medium are processed using cache metadata to identify addresses at which the data items are stored in cache, the identified addresses may be stored in memory. When the computer is later shut down, instead of having to transfer the entirety of the cache metadata from memory to storage, only the subset of the plurality of hierarchy levels and/or the identified addresses previously loaded to memory may be transferred (e.g., to the cache device), thereby expediting the shutdown of the computer.
摘要:
Multiple copy sets of data are maintained on one or more storage devices. Each copy set includes at least some of the same data units as other sets. Different sets optionally have data units stored in different orders on the storage device(s). A particular one of the sets of data is selected as the set to be accessed in response to detecting a particular scenario.
摘要:
Multiple copy sets of data are maintained on one or more storage devices. Each copy set includes at least some of the same data units as other sets. Different sets optionally have data units stored in different orders on the storage device(s). A particular one of the sets of data is selected as the set to be accessed in response to detecting a particular scenario.