A Highly Recoverable Filesystem for Solid State Drives

dc.contributor.advisorWijesekera, Duminda
dc.contributor.authorAlhussein, Mohammed
dc.creatorAlhussein, Mohammed
dc.date2014-08
dc.date.accessioned2014-10-14T20:05:27Z
dc.date.available2019-08-15T06:39:29Z
dc.date.issued2014-10-14
dc.description.abstractRecovering deleted information from storage drives is a long-standing problem. Prior research has approached information recovery by developing file-carving techniques. However, two issues present significant challenges to on-going efforts. 1) Prior knowledge of file types is required to construct file carvers, including file headers and footers, and 2) fragmentation prevents file carvers from achieving successful recovery. More recently, solid state drives or “SSDs” have become more popular. SSDs provide several advantages over traditional mechanical hard drives. They have smaller sizes, are constructed without moving parts, and provide better performance. However, due to problems such as wear leveling and write amplification in SSDs, files are severely fragmented and thus exacerbate the data recovery problem. In addition, SSDs use TRIM and garbage collection schemes to enhance their performance, which can permanently delete data immediately after a delete operation. In this dissertation, I developed a framework for recovering deleted files without knowing the file types and despite significant fragmentation. I developed the Recovery Filesystem by modifying an existing implementation of the exFat filesystem running on top of FUSE. The central idea underlying the Recovery Filesystem is a special identifier embedded in each data block. The identifier monitors each block by mapping the data block to a single file regardless of the file status, existing or deleted. The block sequence number and creation timestamp are also maintained to facilitate the recovery process. In addition, I developed a garbage collection scheme for SSDs that maximizes data retention without sacrificing SSD performance. The experiments conducted in this dissertation demonstrate that the Recovery Filesystem yields acceptable read/write performance results. In addition, file recovery experiments used to compare the Recovery Filesystem with open source recovery techniques demonstrate that the Recovery Filesystem provides significant advantages in the case of fragmented data.
dc.description.noteThis work was embargoed by the author and will not be available until August 2019.
dc.identifier.urihttps://hdl.handle.net/1920/9059
dc.language.isoen_US
dc.rightsCopyright 2014 Mohammed Alhussein
dc.subjectData Recovery
dc.subjectSolid State Drives
dc.titleA Highly Recoverable Filesystem for Solid State Drives
dc.typeDissertation
thesis.degree.disciplineInformation Technology
thesis.degree.grantorGeorge Mason University
thesis.degree.levelDoctoral
thesis.degree.namePhD in Information Technology

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