Charles University in Prague Faculty of Mathematics and Physics DOCTORAL THESIS Mikul´aˇsPatoˇcka Design and Implementation of the Spad Filesystem Department of Software Engineering Advisor: RNDr. Filip Zavoral, Ph.D. Abstract Title: Design and Implementation of the Spad Filesystem Author: Mgr. Mikul´aˇsPatoˇcka email:
[email protected]ff.cuni.cz Department: Department of Software Engineering Faculty of Mathematics and Physics Charles University in Prague, Czech Republic Advisor: RNDr. Filip Zavoral, Ph.D. email: Filip.Zavoral@mff.cuni.cz Mailing address (advisor): Dept. of Software Engineering Charles University in Prague Malostransk´en´am. 25 118 00 Prague, Czech Republic WWW: http://artax.karlin.mff.cuni.cz/~mikulas/spadfs/ Abstract: This thesis describes design and implementation of the Spad filesystem. I present my novel method for maintaining filesystem consistency — crash counts. I describe architecture of other filesystems and present my own de- sign decisions in directory management, file allocation information, free space management, block allocation strategy and filesystem checking algorithm. I experimentally evaluate performance of the filesystem. I evaluate performance of the same filesystem on two different operating systems, enabling the reader to make a conclusion on how much the performance of various tasks is affected by operating system and how much by physical layout of data on disk. Keywords: filesystem, operating system, crash counts, extendible hashing, SpadFS Acknowledgments I would like to thank my advisor Filip Zavoral for supporting my work and for reading and making comments on this thesis. I would also like to thank to colleague Leo Galamboˇsfor testing my filesystem on his search engine with 1TB RAID array, which led to fixing some bugs and improving performance.