Optimal Garbage Collection Scheduling Times Policies for SSD  
Author Syouji Nakamura


Co-Author(s) Mingchih Chen; Xufeng Zhao; Toshio Nakagawa


Abstract This paper considers a garbage collection (GC) models for the solid state drive (SSD); A model of applied cumulative damage model. Hard disk drives(HDD )s can overwrite data directly on the drive in any particular sector. However, SSDs have to be rewritten to previously erased blocks. Therefore, the erased blocks in SSD becomes less. Where the system requires a erase operation of the used blocks in the SSD. This a erase operation is called the garbage collection in SSD. The fundamental GC technique for a SSD is regularly carried out by executing erase operations. However, the overhead of such a erase operation becomes sometimes very large time. To lessen the overhead of GC, a system execute an incremental GC with small overhead. However, the overhead of an incremental GC increase in proportion to the total amount of garbages. It is shown that an optimal interval is given by a finite and unique solution of an equation under suitable conditions.


Keywords Garbage Collection, SSD, Stochastics model, Optimal policy, Expected cost
    Article #:  21252
Proceedings of the 21st ISSAT International Conference on Reliability and Quality in Design
August 6-8, 2015 - Philadelphia, Pennsylvia, U.S.A.