Device for controlling access to units of a storage device
AssigneeFujitsu Limited
InventorMitsuhiko Yashiro
Life of this patent
Estimating the term…
Abstract
A file control device having physical storage devices and logical storage devices, which prevents competition for access to the physical storage device and avoids a decline in performance. When adding a new block to the cache memory or when ejecting a block from cache memory, a block with the lowest access frequency out of data retained in a physical storage device having the lowest access frequency is determined for ejection. The file control device concurrently monitors storage device priority information in addition to data priority information to control transfer of data between the storage device and the cache memory.
Claims19
A file control device, comprising:
- a storage device to store data, the storage device including a plurality of memory devices;
- a cache memory, connected to the plurality of memory devices, to store a portion of the data stored in the storage device;
- and
- a control device to control transfer of data between the storage device and the cache memory,
- wherein the control device controls data transfer between the storage device and the cache memory according to cache data information indicating a relationship between a location in the storage device where the portion of the data is stored and a location in the cache memory where the portion of the data is to be retained, and according to data priority information indicating a priority rank for the data stored in the cache memory, and according to device priority information indicating priority ranks for memory devices of the plurality of memory devices that have data in the cache memory.
A memory system, comprising:
- a memory device including a plurality of storage devices to store data in block units;
- a cache memory connected to the plurality of storage devices to store a portion of the data stored in the plurality of storage devices;
- and
- a control device monitoring frequency of access to each of the plurality of storage devices and separately monitoring access to the blocks of data stored in the storage devices and, according to both monitorings, controlling transfer of data between the storage device and the cache memory,
- wherein the control device controls ejection of data from the cache memory to maximize the probability that different logical storage devices allocated to the same physical storage device can be simultaneously accessed.
A memory system, comprising:
- a memory device including a plurality of storage devices to store data in block units;
- a cache memory connected to the plurality of storage devices to store a portion of the data stored in the plurality of storage devices;
- and
- a control device monitoring access to the plurality of storage devices and monitoring access to the blocks of data stored in the storage devices and, according to the monitoring, controlling transfer of data between the storage device and the cache memory, wherein the control device assigns a priority rank to the plurality of storage devices and assigns a priority rank to the blocks of data stored in the storage devices to concurrently monitor the storage devices and the blocks of data.
A memory system, comprising:
- a memory device including a plurality of storage devices to store data in block units;
- a cache memory connected to the plurality of storage devices to store a portion of the data stored in the plurality of storage devices;
- and
- a control device monitoring access to the plurality of storage devices and separately monitoring access to the blocks of data stored in the storage devices and, according to both monitorings, controlling transfer of data between the storage device and the cache memory, wherein each of the storage devices include a plurality of logical storage devices in which data is stored in block units,
- wherein the control device controls ejection of data from the cache memory to maximize the probability that different logical storage devices allocated to the same physical storage device can be simultaneously accessed.
A memory system, comprising:
- a memory device including a plurality of storage devices to store data in block units;
- a cache memory connected to the plurality of storage devices to store a portion of the data stored in the plurality of storage devices;
- and
- a control device monitoring access to the plurality of storage devices and monitoring access to the blocks of data stored in the storage devices and, according to the monitoring, controlling transfer of data between the storage device and the cache memory wherein the control device comprises:
- a memory monitoring device to monitor priority of the plurality of storage devices connected to the cache memory;
- and
- a data monitoring device to monitor priority of the blocks of data stored in the plurality of storage devices, and
- wherein the memory monitoring device assigns a highest priority to a storage device which stores data for which access has been requested.
A memory system, comprising:
- a memory device including a plurality of storage devices to store data in block units;
- a cache memory connected to the plurality of storage devices to store a portion of the data stored in the plurality of storage devices;
- and
- a control device monitoring access to the plurality of storage devices and monitoring access to the blocks of data stored in the storage devices and, according to the monitoring, controlling transfer of data between the storage device and the cache memory wherein the control device comprises:
- a memory monitoring device to monitor priority of the plurality of storage devices connected to the cache memory;
- and
- a data monitoring device to monitor priority of the blocks of data stored in the plurality of storage devices, and wherein the memory monitoring device assigns a priority to a storage device according to frequency of access to the storage devices, and the data monitoring device assigns priority to a block of data according to frequency of access to the blocks of data.
A method of accessing data stored in a memory system comprising a plurality of storage devices to store blocks of data and a cache memory connected to the plurality of storage devices to store a portion of the data stored in the storage devices, comprising:
- monitoring frequency of access to each of the plurality of storage devices and separately monitoring access to the blocks of data stored in the storage devices and, according to both monitorings, controlling transfer of data between the storage device and the cache memory by storing an entry in a least recently used cache of a storage area in a storage device of the plurality of storage devices, wherein the storage device has a lowest priority.
A method of accessing data stored in a memory system comprising a plurality of storage devices to store blocks of data and a cache memory connected to the plurality of storage devices to store a portion of the data stored in the storage devices, comprising:
- monitoring access to the plurality of storage devices and monitoring access to the blocks of data stored in the storage devices and, according to the monitoring, controlling transfer of data between the storage device and the cache memory
- wherein the concurrently monitoring comprises:
- monitoring priority of the plurality of storage devices connected to the cache memory;
- and
- monitoring priority of the blocks of data stored in the plurality of storage devices, and the method further comprising:
- determining a storage device having the lowest priority;
- determining a block of data having a lowest priority of the blocks of data stored in the storage device having the lowest priority;
- and
- ejecting the block of data determined to have the lowest priority of the blocks of data stored in the storage device having the lowest priority.
A method of ejecting entries from the cache of a multi-device storage unit, comprising selecting a cache entry from among a group of least recently used cache entries, where the cache entry is selected based on its correspondence to a storage device having a lowest cache priority.
A method of controlling a cache, comprising:
- storing entries in a cache, where each entry corresponds to a storage area in one of a plurality of storage devices;
- prioritizing the storage devices based on recency of their use;
- and
- selecting a least recently used cache entry corresponding to a storage area of a low priority storage device.
Dependencies are inferred from the claim text.