Disk array caching method for virtual SSD and SSD isomerous mirror image

Abstract

The invention discloses a disk array caching method for a virtual SSD and an SSD isomerous mirror image. The disk array caching method comprises the steps that a disk is logically divided into two parts, wherein the upper half part forms an RAID0 or RAID5 structure to serve as the virtual SSD so as to back up dirty data in a real SSD, the virtual SSD is in a log writing mode, a ram writing cache is set, and the lower half portion is assembled to be of different RAID structures according to needs of users, and is used as a data array so as to store cold data; an address mapping Hash locating table between a data disk and the cache of the real SSD is built; a timer is set so as to regularly write data cached in the ram writing cache of the virtual SSD into the virtual SSD; a request from an upper layer file system is received; for a reading request, when the reading request is not hit in the real SSD, data are read from the data array. The disk array caching method gives consideration to performance, reliability and cost.

Description

technical field [0001] The invention belongs to the technical field of data storage, and more specifically relates to a disk array caching method for a virtual SSD and a heterogeneous image of the SSD. Background technique [0002] Solid-state drives use flash memory as the storage medium, so compared with traditional disks, there is no mechanical process of head seeking, and their read and write performance is much better than that of disks, especially the random read and write performance. The introduction of SSD into the storage system greatly improves the performance of the entire system. At present, the capacity of SSD is much smaller than that of ordinary disks, and it is difficult to meet the application scenarios of large amounts of data. SSDs are currently used in the industry mainly as hierarchical storage media, and SSD caches. Compared with traditional memory caches, SSDs can provide larger cache space, store frequently accessed hot data in SSDs, and store less ...

AI Technical Summary

Problems solved by technology

[0003] However, there are still the following defects in using a separate SSD as a cache: first, it is expensive, and the price becomes more expensive as the capacity increases; second, the number of erasing and writing of SSDs is limited, and the erasing work will be completed before writing data, compared with ordinary disks , the service life of SSD is shorter, which also causes the reliability problem of using SSD system

[0005] Another common way is to simply use ordinary disks as SSD mirrors to ensure reliability. However, due to the poor performance of ordinary disks compared to SSDs, at this time, when a write hit occurs, data is written to the SSD and the mirror disk at the same time. , obviously the mirrored disk will become a performance bottleneck, greatly reducing the advantage of high-speed SSD cache

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