Systems and methods which provide for improved prefetching schemes for caching data in a storage network are described. In one embodiment, a dynamically adaptive prefetching mechanism based on block access history information and prior effectiveness of prefetching is provided. Embodiments may take into account prefetch efficiency; a dynamic value indicating the usefulness of past prefetches, prefetch wastage, in conjunction with prefetch resources available at any point in time, to determine the number of blocks to read-ahead during a prefetch. Such embodiments provide improvements over file-based prefetching and previous block schemes, as they provide a finer grain of control over both prefetch block selection, and the number of blocks to prefetch based on block (or block range) access history.

Systems and methods for adaptive prefetching

Provided are a method, system, and article of manufacture for adjusting parameters used to prefetch data from storage into cache. Data units are added from a storage to a cache, wherein requested data from the storage is returned from the cache. A degree of prefetch is processed indicating a number of data units to prefetch into the cache. A trigger distance is processed indicating a prefetched trigger data unit in the cache. The number of data units indicated by the degree of prefetch is prefetched in response to processing the trigger data unit. The degree of prefetch and the trigger distance are adjusted based on a rate at which data units are accessed from the cache.

Adjusting parameters used to prefetch data from storage into cache

Techniques for reducing mount time for a peripheral device connected to an external host device are presented. In some implementations, when a connection is detected, file system data is pre-fetched before a request for such data is sent by the external host device. This allows faster access to the file system data used for initiating read/write communications. In other implementations, in response to a data access command from the external host device, a reply message is delayed from the peripheral device to prevent data access command failures. This delayed response prevents the external host device from pausing before attempting subsequent communication requests.

Reducing connection time for mass storage class devices

The present invention relates to backup solutions in electronic computing systems and in particular to a method and respective system for managing the storage of application data on a removable storage medium and mounting the removable medium on a according driver device, wherein the application data is cached in a so-called “virtual tape system”, represented by a random-access storage medium, preferably a hard disk, before being written to removable medium or read from removable medium. In order to provide a method including an improved removable medium mount control for increasing the efficiency of removable medium driver device, it is proposed to perform the steps of: managing mount-specific meta data characteristic for removable medium operation workload tasks; predicting upcoming I/O workload based on said meta data; determining based on said calculation, if or when an incoming mount request for mounting a removable medium will be serviced.

Method and system for writing and reading application data

A method and apparatus for adaptive multiple line prefetching. In one embodiment, the method includes the identification of a prefetch depth. As described herein, a prefetch depth may refer to a number of memory lines to be prefetched to temporary (cache) memory. Once the prefetch depth is identified, prefetching is performed according to the identified prefetch depth. During the prefetching, the prefetching is adjusted as changes in the prefetch depth are detected. Accordingly, the dynamic adaptive multi-line prefetching mechanism described herein promotes higher system performance by the use of a more efficient prefetching mechanism.

Apparatus and method for an adaptive multiple line prefetcher

Exemplary systems, methods, and devices employ receiving an operational parameter characteristic of a storage device, and adapting a read cache pre-fetch depth based in part on the operational parameter. An exemplary device includes a read cache memory and a read cache pre-fetch adaptation module operable to generate an operational parameter and vary read cache pre-fetch depth in response to the operational parameter.

Brian S. Bearden

Papers

Method of adaptive read cache pre-fetching to increase host read throughput