Design And Implementation Of A Cache Policy Based On Solid-state Disk

Conventional cache policy mainly use RAM as cache device and set the speed of readand write as target.With the advent of SSDs,this design no longer applicable as theCharacteristic of SSDs. If the traditional cache design is applied directly to the SSD,notonly will not achieve the disired results, it will result in SSD’life quickly wear out.If asmuch as possible take into account the characteristics of the SSD while disigning cahcepolicy,we will obtain the disired results while not affecting its life.SSD-based Adaptive Cost-Aware cache policy fully takes into account thecharacteristics of the SSDs,combined with traditional cahce policy maximize play therole of SSDS.Its core mechanism is the dynamic adjustment based on access mode andefficient hot data selection algorithm.As the read and write performance of the disk andSSD’s read and write performance differences, the RAM cache is divided into read areaand write area,dynamically adjust the size of the read and write area through the analysisof the current access mode.Meanwhile,minimum time complexity while not increasingspace cost when selecting hot data. In order not to affect the service of the system, hot datamigration is not separately but dispersing the hot data migration after completing theprocessing of read and write requests, thus avoiding the performance impact of the hotdata selection and data migration.Some specialized tools are used to perform an experimental evaluation of SSD-basedAdaptive Cost-Aware cache policy. The results show that SSD-based AdaptiveCost-Aware cache policy can adjust dynamically according to access mode and reduce thesystem’s response time. In the same time, results of the read and write performance of thesystem in the random access show that read performance is improved significantly whilewrite performance has not declined. Moreover, SSD-based Adaptive Cost-Aware cachepolicy is much less than Conventional cache policy in SSD writes.