Write-friendly flash memory solid-state disk cache management method

Abstract

The invention discloses a write-friendly flash memory solid-state disk cache management method, which comprises the following steps of: managing clean data pages in a cache by taking pages as basic units, performing page cluster operation on dirty data pages in the cache according to different flash memory physical blocks to which the dirty data pages belong, and organizing a plurality of data pages of the same flash memory physical block into one page cluster; setting system access time visit _ time to record the number of times of accessing the data page; recording a time stamp of accessingthe data page by the cache; setting a latest access time window; wherein the recent access time window covers a plurality of recently accessed data pages in the cache; setting the size of the recent access time window value tw to be 10% of the size of the cache space; and when the target data of the I / O request is not hit in the cache, reading the target data of the I / O request from the flash memory, returning the target data to the upper-layer application, and inserting the target data page into the corresponding management linked list in the cache according to the read-write type of the I / Orequest. The cache replacement frequency and the flash memory garbage collection overhead are reduced, and the overall performance of the flash memory is improved.

Description

technical field [0001] The invention belongs to the technical field of caching, and in particular relates to a write-friendly flash memory solid state disk cache management method. Background technique [0002] The solid-state disk of flash memory has the advantages of fast access speed, low energy consumption, and good shock resistance. It has received extensive attention and research in industry and academia, and has been widely used in consumer devices, cloud storage, and data centers. However, due to the physical characteristics of flash memory, flash memory SSDs face many constraints such as erasure before writing, asymmetric reading and writing, and limited erasing times. In order to avoid data block erasure and data migration caused by update write operations, the flash memory uses an off-site update strategy to redirect update write operations to reallocated free blocks, thereby avoiding data block erasure for each write operation Operation and data migration, reduc...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a write-friendly flash memory solid state disk cache management method for the shortcomings of existing flash memory solid state disk cache management methods in terms of optimizing write operations. The data page ensures a high cache hit rate, and at the same time allows data with similar addresses and different hot and cold characteristics to be written back to the flash memory together, reducing the cost of flash garbage collection, thereby improving the overall performance of the flash SSD

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