Snapshots in Large-Scale Distributed File Systems
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Copy on Write Based File Systems Performance Analysis and Implementation
Copy On Write Based File Systems Performance Analysis And Implementation Sakis Kasampalis Kongens Lyngby 2010 IMM-MSC-2010-63 Technical University of Denmark Department Of Informatics Building 321, DK-2800 Kongens Lyngby, Denmark Phone +45 45253351, Fax +45 45882673 [email protected] www.imm.dtu.dk Abstract In this work I am focusing on Copy On Write based file systems. Copy On Write is used on modern file systems for providing (1) metadata and data consistency using transactional semantics, (2) cheap and instant backups using snapshots and clones. This thesis is divided into two main parts. The first part focuses on the design and performance of Copy On Write based file systems. Recent efforts aiming at creating a Copy On Write based file system are ZFS, Btrfs, ext3cow, Hammer, and LLFS. My work focuses only on ZFS and Btrfs, since they support the most advanced features. The main goals of ZFS and Btrfs are to offer a scalable, fault tolerant, and easy to administrate file system. I evaluate the performance and scalability of ZFS and Btrfs. The evaluation includes studying their design and testing their performance and scalability against a set of recommended file system benchmarks. Most computers are already based on multi-core and multiple processor architec- tures. Because of that, the need for using concurrent programming models has increased. Transactions can be very helpful for supporting concurrent program- ming models, which ensure that system updates are consistent. Unfortunately, the majority of operating systems and file systems either do not support trans- actions at all, or they simply do not expose them to the users. -
CERIAS Tech Report 2017-5 Deceptive Memory Systems by Christopher N
CERIAS Tech Report 2017-5 Deceptive Memory Systems by Christopher N. Gutierrez Center for Education and Research Information Assurance and Security Purdue University, West Lafayette, IN 47907-2086 DECEPTIVE MEMORY SYSTEMS ADissertation Submitted to the Faculty of Purdue University by Christopher N. Gutierrez In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy December 2017 Purdue University West Lafayette, Indiana ii THE PURDUE UNIVERSITY GRADUATE SCHOOL STATEMENT OF DISSERTATION APPROVAL Dr. Eugene H. Spa↵ord, Co-Chair Department of Computer Science Dr. Saurabh Bagchi, Co-Chair Department of Computer Science Dr. Dongyan Xu Department of Computer Science Dr. Mathias Payer Department of Computer Science Approved by: Dr. Voicu Popescu by Dr. William J. Gorman Head of the Graduate Program iii This work is dedicated to my wife, Gina. Thank you for all of your love and support. The moon awaits us. iv ACKNOWLEDGMENTS Iwould liketothank ProfessorsEugeneSpa↵ord and SaurabhBagchi for their guidance, support, and advice throughout my time at Purdue. Both have been instru mental in my development as a computer scientist, and I am forever grateful. I would also like to thank the Center for Education and Research in Information Assurance and Security (CERIAS) for fostering a multidisciplinary security culture in which I had the privilege to be part of. Special thanks to Adam Hammer and Ronald Cas tongia for their technical support and Thomas Yurek for his programming assistance for the experimental evaluation. I am grateful for the valuable feedback provided by the members of my thesis committee, Professor Dongyen Xu, and Professor Math ias Payer. -
Final Book Completed to Print in PRESS.Cdr
S.Alagiavanan 3rd CSE GRAPHIC CARDS: V.Narendran 3rd CSE HOW THEY WORK voultion of computing over the last decade EVER Yet very few of you know exactly how these has seen a distinct differentiation based on marvels work. Today's graphic cards are the nature of the workload. On the one WONDERED marvels of engineering, with over 50 times the E raw computational power of current CPUs, but hand you have the computing heavy tasks while on the other, there are graphics intensive tasks. Rewind WHAT GOES they have far more specific and streamlined a back a decade, and you will remember almost every ON BEHIND task. There are two aspects to understanding other motherboard having a dedicated display port how a graphics card works. The first is to as the graphics processor was onboard. Also some THE SCENES understand how it works with the rest of the present day processors which sport integrated WHEN YOU components in a personal computer to generate graphics also have IGP ports on the board. But with an image. The second part would be to the graphical workloads getting more advanced and POWER UP understand the role of major components on outputs more realistic, you would need to invest in a video card. dedicated graphics processing unit to divide tasks YOUR between the CPU and the GPU. Another advantage GAME? of having a dedicated graphics processing unit is the fact that it lets your CPU be free to perform READ ON. other tasks. For instance you can rip a movie in the background while playing a game. -
Membrane: Operating System Support for Restartable File Systems Swaminathan Sundararaman, Sriram Subramanian, Abhishek Rajimwale, Andrea C
Membrane: Operating System Support for Restartable File Systems Swaminathan Sundararaman, Sriram Subramanian, Abhishek Rajimwale, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau, Michael M. Swift Computer Sciences Department, University of Wisconsin, Madison Abstract and most complex code bases in the kernel. Further, We introduce Membrane, a set of changes to the oper- file systems are still under active development, and new ating system to support restartable file systems. Mem- ones are introduced quite frequently. For example, Linux brane allows an operating system to tolerate a broad has many established file systems, including ext2 [34], class of file system failures and does so while remain- ext3 [35], reiserfs [27], and still there is great interest in ing transparent to running applications; upon failure, the next-generation file systems such as Linux ext4 and btrfs. file system restarts, its state is restored, and pending ap- Thus, file systems are large, complex, and under develop- plication requests are serviced as if no failure had oc- ment, the perfect storm for numerous bugs to arise. curred. Membrane provides transparent recovery through Because of the likely presence of flaws in their imple- a lightweight logging and checkpoint infrastructure, and mentation, it is critical to consider how to recover from includes novel techniques to improve performance and file system crashes as well. Unfortunately, we cannot di- correctness of its fault-anticipation and recovery machin- rectly apply previous work from the device-driver litera- ery. We tested Membrane with ext2, ext3, and VFAT. ture to improving file-system fault recovery. File systems, Through experimentation, we show that Membrane in- unlike device drivers, are extremely stateful, as they man- duces little performance overhead and can tolerate a wide age vast amounts of both in-memory and persistent data; range of file system crashes. -
Ext4 File System and Crash Consistency
1 Ext4 file system and crash consistency Changwoo Min 2 Summary of last lectures • Tools: building, exploring, and debugging Linux kernel • Core kernel infrastructure • Process management & scheduling • Interrupt & interrupt handler • Kernel synchronization • Memory management • Virtual file system • Page cache and page fault 3 Today: ext4 file system and crash consistency • File system in Linux kernel • Design considerations of a file system • History of file system • On-disk structure of Ext4 • File operations • Crash consistency 4 File system in Linux kernel User space application (ex: cp) User-space Syscalls: open, read, write, etc. Kernel-space VFS: Virtual File System Filesystems ext4 FAT32 JFFS2 Block layer Hardware Embedded Hard disk USB drive flash 5 What is a file system fundamentally? int main(int argc, char *argv[]) { int fd; char buffer[4096]; struct stat_buf; DIR *dir; struct dirent *entry; /* 1. Path name -> inode mapping */ fd = open("/home/lkp/hello.c" , O_RDONLY); /* 2. File offset -> disk block address mapping */ pread(fd, buffer, sizeof(buffer), 0); /* 3. File meta data operation */ fstat(fd, &stat_buf); printf("file size = %d\n", stat_buf.st_size); /* 4. Directory operation */ dir = opendir("/home"); entry = readdir(dir); printf("dir = %s\n", entry->d_name); return 0; } 6 Why do we care EXT4 file system? • Most widely-deployed file system • Default file system of major Linux distributions • File system used in Google data center • Default file system of Android kernel • Follows the traditional file system design 7 History of file system design 8 UFS (Unix File System) • The original UNIX file system • Design by Dennis Ritche and Ken Thompson (1974) • The first Linux file system (ext) and Minix FS has a similar layout 9 UFS (Unix File System) • Performance problem of UFS (and the first Linux file system) • Especially, long seek time between an inode and data block 10 FFS (Fast File System) • The file system of BSD UNIX • Designed by Marshall Kirk McKusick, et al. -
Online Layered File System (OLFS): a Layered and Versioned Filesystem and Performance Analysis
Loyola University Chicago Loyola eCommons Computer Science: Faculty Publications and Other Works Faculty Publications 5-2010 Online Layered File System (OLFS): A Layered and Versioned Filesystem and Performance Analysis Joseph P. Kaylor Konstantin Läufer Loyola University Chicago, [email protected] George K. Thiruvathukal Loyola University Chicago, [email protected] Follow this and additional works at: https://ecommons.luc.edu/cs_facpubs Part of the Computer Sciences Commons Recommended Citation Joe Kaylor, Konstantin Läufer, and George K. Thiruvathukal, Online Layered File System (OLFS): A layered and versioned filesystem and performance analysi, In Proceedings of Electro/Information Technology 2010 (EIT 2010). This Conference Proceeding is brought to you for free and open access by the Faculty Publications at Loyola eCommons. It has been accepted for inclusion in Computer Science: Faculty Publications and Other Works by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 2010 Joseph P. Kaylor, Konstantin Läufer, and George K. Thiruvathukal 1 Online Layered File System (OLFS): A Layered and Versioned Filesystem and Performance Analysis Joe Kaylor, Konstantin Läufer, and George K. Thiruvathukal Loyola University Chicago Department of Computer Science Chicago, IL 60640 USA Abstract—We present a novel form of intra-volume directory implement user mode file system frameworks such as FUSE layering with hierarchical, inheritance-like namespace unifica- [16]. tion. While each layer of an OLFS volume constitutes a subvol- Namespace Unification: Unix supports the ability to ume that can be mounted separately in a fan-in configuration, the entire hierarchy is always accessible (online) and fully navigable mount external file systems from external resources or local through any mounted layer. -
Andrew File System (AFS) Google File System February 5, 2004
Advanced Topics in Computer Systems, CS262B Prof Eric A. Brewer Andrew File System (AFS) Google File System February 5, 2004 I. AFS Goal: large-scale campus wide file system (5000 nodes) o must be scalable, limit work of core servers o good performance o meet FS consistency requirements (?) o managable system admin (despite scale) 400 users in the “prototype” -- a great reality check (makes the conclusions meaningful) o most applications work w/o relinking or recompiling Clients: o user-level process, Venus, that handles local caching, + FS interposition to catch all requests o interaction with servers only on file open/close (implies whole-file caching) o always check cache copy on open() (in prototype) Vice (servers): o Server core is trusted; called “Vice” o servers have one process per active client o shared data among processes only via file system (!) o lock process serializes and manages all lock/unlock requests o read-only replication of namespace (centralized updates with slow propagation) o prototype supported about 20 active clients per server, goal was >50 Revised client cache: o keep data cache on disk, metadata cache in memory o still whole file caching, changes written back only on close o directory updates are write through, but cached locally for reads o instead of check on open(), assume valid unless you get an invalidation callback (server must invalidate all copies before committing an update) o allows name translation to be local (since you can now avoid round-trip for each step of the path) Revised servers: 1 o move -
LLNL Computation Directorate Annual Report (2014)
PRODUCTION TEAM LLNL Associate Director for Computation Dona L. Crawford Deputy Associate Directors James Brase, Trish Damkroger, John Grosh, and Michel McCoy Scientific Editors John Westlund and Ming Jiang Art Director Amy Henke Production Editor Deanna Willis Writers Andrea Baron, Rose Hansen, Caryn Meissner, Linda Null, Michelle Rubin, and Deanna Willis Proofreader Rose Hansen Photographer Lee Baker LLNL-TR-668095 3D Designer Prepared by LLNL under Contract DE-AC52-07NA27344. Ryan Chen This document was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor Lawrence Livermore National Security, LLC, nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, Print Production manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or Lawrence Livermore National Security, LLC. The views and opinions of authors expressed herein do not necessarily state or reflect those of the Charlie Arteago, Jr., and Monarch Print Copy and Design Solutions United States government or Lawrence Livermore National Security, LLC, and shall not be used for advertising or product endorsement purposes. CONTENTS Message from the Associate Director . 2 An Award-Winning Organization . 4 CORAL Contract Awarded and Nonrecurring Engineering Begins . 6 Preparing Codes for a Technology Transition . 8 Flux: A Framework for Resource Management . -
A Survey of Distributed File Systems
A Survey of Distributed File Systems M. Satyanarayanan Department of Computer Science Carnegie Mellon University February 1989 Abstract Abstract This paper is a survey of the current state of the art in the design and implementation of distributed file systems. It consists of four major parts: an overview of background material, case studies of a number of contemporary file systems, identification of key design techniques, and an examination of current research issues. The systems surveyed are Sun NFS, Apollo Domain, Andrew, IBM AIX DS, AT&T RFS, and Sprite. The coverage of background material includes a taxonomy of file system issues, a brief history of distributed file systems, and a summary of empirical research on file properties. A comprehensive bibliography forms an important of the paper. Copyright (C) 1988,1989 M. Satyanarayanan The author was supported in the writing of this paper by the National Science Foundation (Contract No. CCR-8657907), Defense Advanced Research Projects Agency (Order No. 4976, Contract F33615-84-K-1520) and the IBM Corporation (Faculty Development Award). The views and conclusions in this document are those of the author and do not represent the official policies of the funding agencies or Carnegie Mellon University. 1 1. Introduction The sharing of data in distributed systems is already common and will become pervasive as these systems grow in scale and importance. Each user in a distributed system is potentially a creator as well as a consumer of data. A user may wish to make his actions contingent upon information from a remote site, or may wish to update remote information. -
Scanned by Camscanner Annexure - 1 Broad Based Specifications for Forensic Platformfor National Cyber Forensic Laboratory
Scanned by CamScanner Annexure - 1 Broad Based Specifications for Forensic Platformfor National Cyber Forensic Laboratory S. No. Name of the Tool Specifications 1. The integrated Integrated platform that enables centralized case management and web-based access to various digital forensic tools. Forensic Platform Interface to distributed processing support, Role Assignment, Password Cracking and Recovery, Wizard-Driven Multi-Machine, for sharing Customizable Processing. theDigital Forensic Integrated Simultaneous access to Forensic Lab, Attorneys and Investigators through centralised management console via web interface. tools with suitable Automate email notifications regarding case state. Should include the following with APIs APIs. o FTK Standalone Perpetual Licences – 10 Nos. o AccessData Lab - FTK Connection – 10 Nos. o AccessData Lab - Web User Account – 10 Nos. o Magnet AXIOM Complete Perpetual Licences – 10 Nos. o Comprehensive Mac and iOS forensic analysis and reporting software – 10 Nos. o Belkasoft Evidence Centre Perpetual Licences with integration – 10 Nos. o SPEKTOR Drive with 64GB USB drive running SPEKTOR software Black fabric case 1 x 1 TB collector 1 x 8GB USB Drive for exporting FIVE years' support and updates – 10 Nos. The solution should be deployed/operated on the inhouse Data Centre at CFSL, Hyderabad. The required server hardware and software components for the Integrated API is the responsibility of the solution provider. The platform should be flexible enough to accommodate more number of licences as per the need in future. Perpetual Licencing with 03 years warranty with support for updates up to 05 years. Solution should include certified training for 10 Experts from OEM with in India or at OEM location. -
Title Smart Cites Forensics-Evaluating the Challenges of MK Smart City Forensics Name Ebenezer Okai
Title Smart Cites Forensics-Evaluating the Challenges of MK Smart City Forensics Name Ebenezer Okai This is a digitised version of a dissertation submitted to the University of Bedfordshire. It is available to view only. This item is subject to copyright. INSTITUTE FOR RESEARCH IN APPLICABLE COMPUTING (IRAC) MASTERS BY RESEARCH MODE OF STUDY: FULL TIME Ebenezer Okai ID: 0708426 Smart Cites Forensics-Evaluating the Challenges of MK Smart City Forensics June 2019 I | P a g e Declaration “I, Ebenezer Okai declare that this thesis and the work presented in it are my own and has been generated by me as the result of my own original research. I confirm that: • This work was done wholly or mainly while in candidature for a research degree at this University; • Where any part of this thesis has previously been submitted for a degree or any other qualification at this University or any other institution, this has been clearly stated; • Where I have drawn on or cited the published work of others, this is always clearly attributed; • Where I have quoted from the work of others, the source is always given. With the exception of such quotations, this thesis is entirely my own work; • I have acknowledged all main sources of help; • Where the thesis or any part of it is based on work done by myself jointly with others, I have made clear exactly what was done by others and what I have contributed myself; • Either none of this work has been published before submission, or parts of this work have been published. -
Changeman ZMF Java/Zfs Getting Started Guide
ChangeManZMF Java / zFS Getting Started Guide © Copyright 2010 - 2018 Micro Focus or one of its affiliates. This document, as well as the software described in it, is furnished under license and may be used or copied only in accordance with the terms of such license. Except as permitted by such license, no part of this publication may be reproduced, photocopied, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, recording, or otherwise, without the prior written permission of Serena. Any reproduction of such software product user documentation, regardless of whether the documentation is reproduced in whole or in part, must be accompanied by this copyright statement in its entirety, without modification. The only warranties for products and services of Micro Focus and its affiliates and licensors ("Micro Focus") are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. Micro Focus shall not be liable for technical or editorial errors or omissions contained herein. The information contained herein is subject to change without notice. Contains Confidential Information. Except as specifically indicated otherwise, a valid license is required for possession, use or copying. Consistent with FAR 12.211 and 12.212, Commercial Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U.S. Government under vendor's standard commercial license. Third party programs included with the ChangeMan ZMF product are subject to a restricted use license and can only be used in conjunction with ChangeMan ZMF.