Stochastic modeling and optimization of garbage collection algorithms in solid-state drive systems

2014 ◽  
Vol 77 (2) ◽  
pp. 115-148 ◽  
Author(s):  
Yongkun Li ◽  
Patrick P. C. Lee ◽  
John C. S. Lui
Author(s):  
Chihiro Matsui ◽  
Asuka Arakawa ◽  
Chao Sun ◽  
Tomoko Ogura Iwasaki ◽  
Ken Takeuchi

2021 ◽  
Vol 11 (24) ◽  
pp. 11842
Author(s):  
Gijun Oh ◽  
Junseok Yang ◽  
Sungyong Ahn

Log-structured merge-tree (LSM-Tree)-based key–value stores are attracting attention for their high I/O (Input/Output) performance due to their sequential write characteristics. However, excessive writes caused by compaction shorten the lifespan of the Solid-state Drive (SSD). Therefore, there are several studies aimed at reducing garbage collection overhead by using Zoned Namespace ZNS; SSD in which the host can determine data placement. However, the existing studies have limitations in terms of performance improvement because the lifetime and hotness of key–value data are not considered. Therefore, in this paper, we propose a technique to minimize the space efficiency and garbage collection overhead of SSDs by arranging them according to the characteristics of key–value data. The proposed method was implemented by modifying ZenFS of RocksDB and, according to the result of the performance evaluation, the space efficiency could be improved by up to 75%.


2018 ◽  
Vol 39 (12) ◽  
pp. 1908-1911
Author(s):  
Eung Chang Lee ◽  
Jinsung Rho ◽  
Heeyoub Kang ◽  
Bong Jae Lee

Author(s):  
Imam Riadi ◽  
Rusydi Umar ◽  
Imam Mahfudl Nasrulloh

The rapid development of computer technology in hardware, is currently developing non-volatile computer storage media Solid State Drive (SSD). SSD technology has a faster data access speed than Hard Disk and is currently starting to replace Hard Disk storage media. Freezing software on computer systems is often carried out by computer technicians, because it can save a computer maintenance costs due to errors, be exposed to computer viruses or malware. This software is used to prevent unwanted changes to the computer system, when the computer is restarted changes that occur in the computer system will not be stored on storage media. When this happens, what should be done by digital forensic investigators. This study discusses experimental forensic investigations on SSD media storage with frozen conditions or in this study said the frozen SSD. Frozen SSD is the condition of the drive that is locked so that there is no change in the computer system. Software used to lock and prevent changes such as Deep Freeze, Shadow Defender, Windows Steady State, and Toolwiz Time Freeze. Forensic research stages using methods NIST. The result shows that from comparative analysis conducted with Deep Freeze the results of the RecoverMyFile gives 76.38% and Autopsy gives 75,27%, while frozen condition with Shadow Defender the results of the RecoverMyFile gives 59.72% and Autopsy gives 74.44%. So the results of this study indicate the drive freezing software has an effect obtained can be an obstacle in the digital forensic process.  


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