The design and implementation of a log-structured file system
ACM Transactions on Computer Systems (TOCS)
A performance comparison of RAID-5 and log-structured arrays
HPDC '95 Proceedings of the 4th IEEE International Symposium on High Performance Distributed Computing
Real-time garbage collection for flash-memory storage systems of real-time embedded systems
ACM Transactions on Embedded Computing Systems (TECS)
Design tradeoffs for SSD performance
ATC'08 USENIX 2008 Annual Technical Conference on Annual Technical Conference
Write amplification analysis in flash-based solid state drives
SYSTOR '09 Proceedings of SYSTOR 2009: The Israeli Experimental Systems Conference
Analytic modeling of SSD write performance
Proceedings of the 5th Annual International Systems and Storage Conference
A mean field model for a class of garbage collection algorithms in flash-based solid state drives
Proceedings of the ACM SIGMETRICS/international conference on Measurement and modeling of computer systems
Proceedings of the ACM SIGMETRICS/international conference on Measurement and modeling of computer systems
HEC: improving endurance of high performance flash-based cache devices
Proceedings of the 6th International Systems and Storage Conference
Improving flash write performance by using update frequency
Proceedings of the VLDB Endowment
Password-based single-file encryption and secure data deletion for solid-state drive
Proceedings of the 8th International Conference on Ubiquitous Information Management and Communication
Analytic Models of SSD Write Performance
ACM Transactions on Storage (TOS)
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In flash-based solid-state drives (SSD) and log-structured file systems, new data is written out-of-place, which over time exhausts the available free space. New free space is created by the garbage-collection process, which reclaims the space occupied by invalidated data. The write amplification, incurred because of the additional write operations performed by the garbage-collection mechanism is a critical factor that negatively affects the lifetime and endurance of SSDs. We develop two complementary theoretical models of the SSD operation for uniformly-distributed random small user writes: a Markov chain model, which is useful to explore the performance characteristics of small and medium-sized systems, and a second model that captures the behavior of large systems. The combination of both models allows us to comprehensively characterize the system operation and behavior. Results of theoretical and practical importance are analytically derived and confirmed by means of simulation. Our results demonstrate that (i) as the system occupancy increases, the write amplification increases; (ii) as the number of blocks increases, the write amplification decreases and approaches a lower bound; and (iii) as the number of pages contained in a block increases, the write amplification increases and approaches an upper bound. They also show that, for large systems, the number of free pages reclaimed by the greedy garbage-collection mechanism after each block recycling takes one of two successive values, which provides a quasi-deterministic performance guarantee.