Extension Framework for File Systems in User Space
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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. -
Cryptomator Documentation Release 1.5.0
Cryptomator Documentation Release 1.5.0 Cryptobot Sep 15, 2021 Desktop 1 Setup 3 1.1 Windows...............................................3 1.2 macOS................................................3 1.3 Linux.................................................3 2 Getting Started 5 3 Adding Vaults 7 3.1 Create a New Vault..........................................8 3.2 Open an Existing Vault........................................ 13 4 Accessing Vaults 15 4.1 Unlocking a Vault.......................................... 16 4.2 Working with the Unlocked Vault.................................. 17 4.3 Locking a vault............................................ 18 5 Password And Recovery Key 21 5.1 Change Password........................................... 21 5.2 Show Recovery Key......................................... 22 5.3 Reset Password............................................ 23 6 Vault Mounting 27 6.1 General Adapter Selection...................................... 27 6.2 Options applicable to all Systems and Adapters........................... 27 6.3 WebDAV-specific options...................................... 28 6.4 Dokany-specific options....................................... 28 6.5 FUSE-specific options........................................ 28 7 Vault Management 29 7.1 Remove Vaults............................................ 29 7.2 Reorder Vaults............................................ 29 7.3 Vault Options............................................. 29 8 Setup 33 8.1 Google PlayStore.......................................... -
The Linux Kernel Module Programming Guide
The Linux Kernel Module Programming Guide Peter Jay Salzman Michael Burian Ori Pomerantz Copyright © 2001 Peter Jay Salzman 2007−05−18 ver 2.6.4 The Linux Kernel Module Programming Guide is a free book; you may reproduce and/or modify it under the terms of the Open Software License, version 1.1. You can obtain a copy of this license at http://opensource.org/licenses/osl.php. This book is distributed in the hope it will be useful, but without any warranty, without even the implied warranty of merchantability or fitness for a particular purpose. The author encourages wide distribution of this book for personal or commercial use, provided the above copyright notice remains intact and the method adheres to the provisions of the Open Software License. In summary, you may copy and distribute this book free of charge or for a profit. No explicit permission is required from the author for reproduction of this book in any medium, physical or electronic. Derivative works and translations of this document must be placed under the Open Software License, and the original copyright notice must remain intact. If you have contributed new material to this book, you must make the material and source code available for your revisions. Please make revisions and updates available directly to the document maintainer, Peter Jay Salzman <[email protected]>. This will allow for the merging of updates and provide consistent revisions to the Linux community. If you publish or distribute this book commercially, donations, royalties, and/or printed copies are greatly appreciated by the author and the Linux Documentation Project (LDP). -
Software User Guide
Software User Guide • For the safe use of your camera, be sure to read the “Safety Precautions” thoroughly before use. • Types of software installed on your computer varies depending on the method of installation from the Caplio Software CD-ROM. For details, see the “Camera User Guide”. Using These Manuals How to Use the The two manuals included are for your Caplio Software User Guide 500SE. Display examples: 1. Understanding How to Use Your The LCD Monitor Display examples may be Camera different from actual display screens. “Camera User Guide” (Printed manual) Terms: This guide explains the usage and functions In this guide, still images, movies, and sounds of the camera. You will also see how to install are all referred to as “images” or “files”. the provided software on your computer. Symbols: This guide uses the following symbols and conventions: Caution Caution This indicates important notices and restrictions for using this camera. 2. Downloading Images to Your Computer “Software User Guide” Note *This manual (this file) This indicates supplementary explanations and useful This guide explains how to download images tips about camera operations. from the camera to your computer using the provided software. Refer to This indicates page(s) relevant to a particular function. “P. xx” is used to refer you to pages in this manual. Term 3. Displaying Images on Your This indicates terms that are useful for understanding Computer the explanations. The provided software “ImageMixer” allows you to display and edit images on your computer. For details on how to use ImageMixer, click the [?] button on the ImageMixer window and see the displayed manual. -
File Systems and Disk Layout I/O: the Big Picture
File Systems and Disk Layout I/O: The Big Picture Processor interrupts Cache Memory Bus I/O Bridge Main I/O Bus Memory Disk Graphics Network Controller Controller Interface Disk Disk Graphics Network 1 Rotational Media Track Sector Arm Cylinder Platter Head Access time = seek time + rotational delay + transfer time seek time = 5-15 milliseconds to move the disk arm and settle on a cylinder rotational delay = 8 milliseconds for full rotation at 7200 RPM: average delay = 4 ms transfer time = 1 millisecond for an 8KB block at 8 MB/s Bandwidth utilization is less than 50% for any noncontiguous access at a block grain. Disks and Drivers Disk hardware and driver software provide basic facilities for nonvolatile secondary storage (block devices). 1. OS views the block devices as a collection of volumes. A logical volume may be a partition ofasinglediskora concatenation of multiple physical disks (e.g., RAID). 2. OS accesses each volume as an array of fixed-size sectors. Identify sector (or block) by unique (volumeID, sector ID). Read/write operations DMA data to/from physical memory. 3. Device interrupts OS on I/O completion. ISR wakes up process, updates internal records, etc. 2 Using Disk Storage Typical operating systems use disks in three different ways: 1. System calls allow user programs to access a “raw” disk. Unix: special device file identifies volume directly. Any process that can open thedevicefilecanreadorwriteany specific sector in the disk volume. 2. OS uses disk as backing storage for virtual memory. OS manages volume transparently as an “overflow area” for VM contents that do not “fit” in physical memory. -
Enhancing the Accuracy of Synthetic File System Benchmarks Salam Farhat Nova Southeastern University, [email protected]
Nova Southeastern University NSUWorks CEC Theses and Dissertations College of Engineering and Computing 2017 Enhancing the Accuracy of Synthetic File System Benchmarks Salam Farhat Nova Southeastern University, [email protected] This document is a product of extensive research conducted at the Nova Southeastern University College of Engineering and Computing. For more information on research and degree programs at the NSU College of Engineering and Computing, please click here. Follow this and additional works at: https://nsuworks.nova.edu/gscis_etd Part of the Computer Sciences Commons Share Feedback About This Item NSUWorks Citation Salam Farhat. 2017. Enhancing the Accuracy of Synthetic File System Benchmarks. Doctoral dissertation. Nova Southeastern University. Retrieved from NSUWorks, College of Engineering and Computing. (1003) https://nsuworks.nova.edu/gscis_etd/1003. This Dissertation is brought to you by the College of Engineering and Computing at NSUWorks. It has been accepted for inclusion in CEC Theses and Dissertations by an authorized administrator of NSUWorks. For more information, please contact [email protected]. Enhancing the Accuracy of Synthetic File System Benchmarks by Salam Farhat A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor in Philosophy in Computer Science College of Engineering and Computing Nova Southeastern University 2017 We hereby certify that this dissertation, submitted by Salam Farhat, conforms to acceptable standards and is fully adequate in scope and quality to fulfill the dissertation requirements for the degree of Doctor of Philosophy. _____________________________________________ ________________ Gregory E. Simco, Ph.D. Date Chairperson of Dissertation Committee _____________________________________________ ________________ Sumitra Mukherjee, Ph.D. Date Dissertation Committee Member _____________________________________________ ________________ Francisco J. -
Gluster Roadmap: Recent Improvements and Upcoming Features
Gluster roadmap: Recent improvements and upcoming features Niels de Vos GlusterFS co-maintainer [email protected] Agenda ● Introduction into Gluster ● Quick Start ● Current stable releases ● History of feature additions ● Plans for the upcoming 3.8 and 4.0 release ● Detailed description of a few select features FOSDEM, 30 January 2016 2 What is GlusterFS? ● Scalable, general-purpose storage platform ● POSIX-y Distributed File System ● Object storage (swift) ● Distributed block storage (qemu) ● Flexible storage (libgfapi) ● No Metadata Server ● Heterogeneous Commodity Hardware ● Flexible and Agile Scaling ● Capacity – Petabytes and beyond ● Performance – Thousands of Clients FOSDEM, 30 January 2016 3 Terminology ● Brick ● Fundamentally, a filesystem mountpoint ● A unit of storage used as a capacity building block ● Translator ● Logic between the file bits and the Global Namespace ● Layered to provide GlusterFS functionality FOSDEM, 30 January 2016 4 Terminology ● Volume ● Bricks combined and passed through translators ● Ultimately, what's presented to the end user ● Peer / Node ● Server hosting the brick filesystems ● Runs the Gluster daemons and participates in volumes ● Trusted Storage Pool ● A group of peers, like a “Gluster cluster” FOSDEM, 30 January 2016 5 Scale-out and Scale-up FOSDEM, 30 January 2016 6 Distributed Volume ● Files “evenly” spread across bricks ● Similar to file-level RAID 0 ● Server/Disk failure could be catastrophic FOSDEM, 30 January 2016 7 Replicated Volume ● Copies files to multiple bricks ● Similar to file-level -
Storage Virtualization for KVM – Putting the Pieces Together
Storage Virtualization for KVM – Putting the pieces together Bharata B Rao – [email protected] Deepak C Shettty – [email protected] M Mohan Kumar – [email protected] (IBM Linux Technology Center, Bangalore) Balamurugan Aramugam - [email protected] Shireesh Anjal – [email protected] (RedHat, Bangalore) Aug 2012 LPC2012 Linux is a registered trademark of Linus Torvalds. Agenda ● Problems around storage in virtualization ● GlusterFS as virt-ready file system – QEMU-GlusterFS integration – GlusterFS – Block device translator ● Virtualization management - oVirt and VDSM – VDSM-GlusterFS integration ● Storage integration – libstoragemgmt Problems in storage/FS in KVM virtualization ● Multiple choices for file system and virtualization management ● Lack of virtualization aware file systems ● File systems/storage functionality implemented in other layers of virtualization stack – Snapshots, block streaming, image formats in QEMU ● No well defined interface points in the virtualization stack for storage integration ● No standard interface/APIs available for services like backup and restore ● Need for a single FS/storage solution that works for local, SAN and NAS storage – Mixing different types of storage into a single filesystem namespace GlusterFS ● User space distributed file system that scales to several petabytes ● Aggregates storage resources from multiple nodes and presents a unified file system namespace GlusterFS - features ● Replication ● Striping ● Distribution ● Geo-replication/sync ● Online volume extension -
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. -
End-User Computing Security Guidelines Previous Screen Ron Hale Payoff Providing Effective Security in an End-User Computing Environment Is a Challenge
86-10-10 End-User Computing Security Guidelines Previous screen Ron Hale Payoff Providing effective security in an end-user computing environment is a challenge. First, what is meant by security must be defined, and then the services that are required to meet management's expectations concerning security must be established. This article examines security within the context of an architecture based on quality. Problems Addressed This article examines security within the context of an architecture based on quality. To achieve quality, the elements of continuity, confidentiality, and integrity need to be provided. Confidentiality as it relates to quality can be defined as access control. It includes an authorization process, authentication of users, a management capability, and auditability. This last element, auditability, extends beyond a traditional definition of the term to encompass the ability of management to detect unusual or unauthorized circumstances and actions and to trace events in an historical fashion. Integrity, another element of quality, involves the usual components of validity and accuracy but also includes individual accountability. All information system security implementations need to achieve these components of quality in some fashion. In distributed and end-user computing environments, however, they may be difficult to implement. The Current Security Environment As end-user computing systems have advanced, many of the security and management issues have been addressed. A central administration capability and an effective level of access authorization and authentication generally exist for current systems that are connected to networks. In prior architectures, the network was only a transport mechanism. In many of the systems that are being designed and implemented today, however, the network is the system and provides many of the security services that had been available on the mainframe. -
Globalfs: a Strongly Consistent Multi-Site File System
GlobalFS: A Strongly Consistent Multi-Site File System Leandro Pacheco Raluca Halalai Valerio Schiavoni University of Lugano University of Neuchatelˆ University of Neuchatelˆ Fernando Pedone Etienne Riviere` Pascal Felber University of Lugano University of Neuchatelˆ University of Neuchatelˆ Abstract consistency, availability, and tolerance to partitions. Our goal is to ensure strongly consistent file system operations This paper introduces GlobalFS, a POSIX-compliant despite node failures, at the price of possibly reduced geographically distributed file system. GlobalFS builds availability in the event of a network partition. Weak on two fundamental building blocks, an atomic multicast consistency is suitable for domain-specific applications group communication abstraction and multiple instances of where programmers can anticipate and provide resolution a single-site data store. We define four execution modes and methods for conflicts, or work with last-writer-wins show how all file system operations can be implemented resolution methods. Our rationale is that for general-purpose with these modes while ensuring strong consistency and services such as a file system, strong consistency is more tolerating failures. We describe the GlobalFS prototype in appropriate as it is both more intuitive for the users and detail and report on an extensive performance assessment. does not require human intervention in case of conflicts. We have deployed GlobalFS across all EC2 regions and Strong consistency requires ordering commands across show that the system scales geographically, providing replicas, which needs coordination among nodes at performance comparable to other state-of-the-art distributed geographically distributed sites (i.e., regions). Designing file systems for local commands and allowing for strongly strongly consistent distributed systems that provide good consistent operations over the whole system. -
Glusterfs Documentation Release 3.8.0
GlusterFS Documentation Release 3.8.0 Gluster Community Aug 10, 2016 Contents 1 Quick Start Guide 3 1.1 Single Node Cluster...........................................3 1.2 Multi Node Cluster............................................4 2 Overview and Concepts 7 2.1 Volume Types..............................................7 2.2 FUSE................................................... 10 2.3 Translators................................................ 12 2.4 Geo-Replication............................................. 17 2.5 Terminologies.............................................. 19 3 Installation Guide 23 3.1 Getting Started.............................................. 23 3.2 Configuration............................................... 24 3.3 Installing Gluster............................................. 26 3.4 Overview................................................. 27 3.5 Quick Start Guide............................................ 28 3.6 Setup Baremetal............................................. 29 3.7 Deploying in AWS............................................ 30 3.8 Setting up in virtual machines...................................... 31 4 Administrator Guide 33 5 Upgrade Guide 35 6 Contributors Guide 37 6.1 Adding your blog............................................. 37 6.2 Bug Lifecycle.............................................. 37 6.3 Bug Reporting Guidelines........................................ 38 6.4 Bug Triage Guidelines.......................................... 41 7 Changelog 47 8 Presentations 49 i ii GlusterFS