Caching less for better performance: Balancing cache size and update cost of flash memory cache in hybrid storage systems

Yongseok Oh, Jongmoo Choi, Donghee Lee, Sam H. Noh

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

103 Scopus citations

Abstract

Hybrid storage solutions use NAND flash memory based Solid State Drives (SSDs) as non-volatile cache and traditional Hard Disk Drives (HDDs) as lower level storage. Unlike a typical cache, internally, the flash memory cache is divided into cache space and over-provisioned space, used for garbage collection. We show that balancing the two spaces appropriately helps improve the performance of hybrid storage systems. We show that contrary to expectations, the cache need not be filled with data to the fullest, but may be better served by reserving space for garbage collection. For this balancing act, we present a dynamic scheme that further divides the cache space into read and write caches and manages the three spaces according to the workload characteristics for optimal performance. Experimental results show that our dynamic scheme improves performance of hybrid storage solutions up to the off-line optimal performance of a fixed partitioning scheme. Furthermore, as our scheme makes efficient use of the flash memory cache, it reduces the number of erase operations thereby extending the lifetime of SSDs.

Original languageEnglish
Title of host publicationProceedings of FAST 2012
Subtitle of host publication10th USENIX Conference on File and Storage Technologies
PublisherUSENIX Association
Pages313-326
Number of pages14
ISBN (Electronic)9781931971911
StatePublished - 2012
Event10th USENIX Conference on File and Storage Technologies, FAST 2012 - San Jose, United States
Duration: 15 Feb 201217 Feb 2012

Publication series

NameProceedings of FAST 2012: 10th USENIX Conference on File and Storage Technologies

Conference

Conference10th USENIX Conference on File and Storage Technologies, FAST 2012
Country/TerritoryUnited States
CitySan Jose
Period15/02/1217/02/12

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