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1、Steven SprouseDeterministic,Fast,Random Preconditioning Using Sprandom in FIODeterministic,Fast,Random Preconditioning Using“Sprandom”in FIOSteven SprouseSTORAGETime spent testing is more valuable than time spent preparing the testPrevious time constraints were convenient,but:As SSD capacities incre
2、ase beyond 16TB,the time to randomly precondition these drives has also increased from several hours to several days.Brute force used to work,but:Traditional methods involve at least one sequential write followed by multiple random writes to reach a steady state.A single sequential write on a 128TB
3、drive can take 10 hours.Logically fill the drive:Every LBA shall be written once.Achieved by at least one logical drive writeReach a steady state throughput:Achieved through several random drive writes.Overprovisioning is distributed within the drive in a particular way.The Mechanics of Pre-Conditio
4、ning SSDsThe figure to the right shows roughly how the OP is distributed across the physical media in an SSD when a random write workload reaches steady state.In this example,there is 15%OP in the drive.What is the ideal“Pre-Conditioned”State?Goal:Combine the Fill and Steady State in a single pass.L
5、ogical Drive fills were taking too long,and required more time as capacities increased.Could we shape writes in a way that will still write every LBA at least once,while forcing the drive to go into garbage collection saving time on subsequent sequential or random writes?Steady state throughput is m
6、easurable,so we can compare methodologiesTest apples to apples after traditional and SPRandom pre-conditioning to ensure steady state operationReport and measure overprovisioning use and compare between methodologiesSanDisk Pseudo-Random Fast Preconditioning(SPRandom)Preconditioning redistributes ov