(SAN, RAID, SATA) Make File/Disk Defragmentation Obsolete?
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SAS Enters the Mainstream Although Adoption of Serial Attached SCSI
SAS enters the mainstream By the InfoStor staff http://www.infostor.com/articles/article_display.cfm?Section=ARTCL&C=Newst&ARTICLE_ID=295373&KEYWORDS=Adaptec&p=23 Although adoption of Serial Attached SCSI (SAS) is still in the infancy stages, the next 12 months bode well for proponents of the relatively new disk drive/array interface. For example, in a recent InfoStor QuickVote reader poll, 27% of the respondents said SAS will account for the majority of their disk drive purchases over the next year, although Serial ATA (SATA) topped the list with 37% of the respondents, followed by Fibre Channel with 32%. Only 4% of the poll respondents cited the aging parallel SCSI interface (see figure). However, surveys of InfoStor’s readers are skewed by the fact that almost half of our readers are in the channel (primarily VARs and systems/storage integrators), and the channel moves faster than end users in terms of adopting (or at least kicking the tires on) new technologies such as serial interfaces. Click here to enlarge image To get a more accurate view of the pace of adoption of serial interfaces such as SAS, consider market research predictions from firms such as Gartner and International Data Corp. (IDC). Yet even in those firms’ predictions, SAS is coming on surprisingly strong, mostly at the expense of its parallel SCSI predecessor. For example, Gartner predicts SAS disk drives will account for 16.4% of all multi-user drive shipments this year and will garner almost 45% of the overall market in 2009 (see figure on p. 18). -
Relieving the Burden of Track Switch in Modern Hard Disk Drives
Multimedia Systems DOI 10.1007/s00530-010-0218-5 REGULAR PAPER Relieving the burden of track switch in modern hard disk drives Jongmin Gim • Youjip Won Received: 11 November 2009 / Accepted: 22 November 2010 Ó Springer-Verlag 2010 Abstract In this work, we propose a novel hard disk 128 KByte, 17% of the disk space becomes unusable. technique, ‘‘AV Disk’’, for modern multimedia applica- Despite the decreased storage area, track aligning tech- tions. Modern hard disk drives adopt complex sector layout nique increases the overall performance of the hard disk. mechanisms to reduce track and head switch overhead. According to our simulation-based experiment, overall disk While these complex sector layout mechanism can reduce performance increases about 5–25%. Given that capacity of average overhead involved in the track and head switch, hard disk increases 100% every year, we cautiously regard they bring larger variability in the overhead. From a it as reasonable tradeoff to increase the I/O latency of the multimedia application’s point of view, it is important to disk. minimize the worst case I/O latency rather than to improve the average IO latency. We focus our effort to minimize Keyword Hard disk drive Á Multimedia Á Track align Á track switch overhead as well as the variability in track Track switch Á Sector geometry Á Audio and video switch overhead involved in disk I/O. We propose that track of the hard disk drive is aligned with a certain IO size. In this work, we develop an elaborate performance model 1 Introduction with which we can compute the optimal IO unit size for multimedia applications. -
Fragmentation in Large Object Repositories
Fragmentation in Large Object Repositories Experience Paper Russell Sears Catharine van Ingen University of California, Berkeley Microsoft Research [email protected] [email protected] ABSTRACT 1. INTRODUCTION Fragmentation leads to unpredictable and degraded application Application data objects continue to increase in size. performance. While these problems have been studied in detail Furthermore, the increasing popularity of web services and other for desktop filesystem workloads, this study examines newer network applications means that systems that once managed static systems such as scalable object stores and multimedia archives of “finished” objects now manage frequently modified repositories. Such systems use a get/put interface to store objects. versions of application data. Rather than updating these objects in In principle, databases and filesystems can support such place, typical archives either store multiple versions of the objects applications efficiently, allowing system designers to focus on (the V of WebDAV stands for “versioning” [25]), or simply do complexity, deployment cost and manageability. wholesale replacement (as in SharePoint Team Services [19]). Similarly, applications such as personal video recorders and Although theoretical work proves that certain storage policies media subscription servers continuously allocate and delete large, behave optimally for some workloads, these policies often behave transient objects. poorly in practice. Most storage benchmarks focus on short-term behavior or do not measure fragmentation. We compare SQL Applications store large objects as some combination of files in Server to NTFS and find that fragmentation dominates the filesystem and as BLOBs (binary large objects) in a database. performance when object sizes exceed 256KB-1MB. NTFS Only folklore is available regarding the tradeoffs. -
ECE 598 – Advanced Operating Systems Lecture 19
ECE 598 { Advanced Operating Systems Lecture 19 Vince Weaver http://web.eece.maine.edu/~vweaver [email protected] 7 April 2016 Announcements • Homework #7 was due • Homework #8 will be posted 1 Why use FAT over ext2? • FAT simpler, easy to code • FAT supported on all major OSes • ext2 faster, more robust filename and permissions 2 btrfs • B-tree fs (similar to a binary tree, but with pages full of leaves) • overwrite filesystem (overwite on modify) vs CoW • Copy on write. When write to a file, old data not overwritten. Since old data not over-written, crash recovery better Eventually old data garbage collected • Data in extents 3 • Copy-on-write • Forest of trees: { sub-volumes { extent-allocation { checksum tree { chunk device { reloc • On-line defragmentation • On-line volume growth 4 • Built-in RAID • Transparent compression • Snapshots • Checksums on data and meta-data • De-duplication • Cloning { can make an exact snapshot of file, copy-on- write different than link, different inodles but same blocks 5 Embedded • Designed to be small, simple, read-only? • romfs { 32 byte header (magic, size, checksum,name) { Repeating files (pointer to next [0 if none]), info, size, checksum, file name, file data • cramfs 6 ZFS Advanced OS from Sun/Oracle. Similar in idea to btrfs indirect still, not extent based? 7 ReFS Resilient FS, Microsoft's answer to brtfs and zfs 8 Networked File Systems • Allow a centralized file server to export a filesystem to multiple clients. • Provide file level access, not just raw blocks (NBD) • Clustered filesystems also exist, where multiple servers work in conjunction. -
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. -
Engineering Specifications
DOC NO : Rev. Issued Date : 2020/10/08 V1.0 SOLID STATE STORAGE TECHNOLOGY CORPORATION 司 Revised Date : ENGINEERING SPECIFICATIONS Product Name: CVB-CDXXX (WT) Model CVB-CD128 CVB-CD256 CVB-CD512 CVB-CD1024 Author: Ken Liao DOC NO : Rev. Issued Date : 2020/10/08 V1.0 SOLID STATE STORAGE TECHNOLOGY CORPORATION 司 Revised Date : Version History Date 0.1 Draft 2020/07/20 1.0 First release 2020/10/08 DOC NO : Rev. Issued Date : 2020/10/08 V1.0 SOLID STATE STORAGE TECHNOLOGY CORPORATION 司 Revised Date : Copyright 2020 SOLID STATE STORAGE TECHNOLOGY CORPORATION Disclaimer The information in this document is subject to change without prior notice in order to improve reliability, design, and function and does not represent a commitment on the part of the manufacturer. In no event will the manufacturer be liable for direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the product or documentation, even if advised of the possibility of such damages. This document contains proprietary information protected by copyright. All rights are reserved. No part of this datasheet may be reproduced by any mechanical, electronic, or other means in any form without prior written permission of SOLID STATE STORAGE Technology Corporation. DOC NO : Rev. Issued Date : 2020/10/08 V1.0 SOLID STATE STORAGE TECHNOLOGY CORPORATION 司 Revised Date : Table of Contents 1 Introduction ....................................................................... 5 1.1 Overview ............................................................................................. -
Filesystem Considerations for Embedded Devices ELC2015 03/25/15
Filesystem considerations for embedded devices ELC2015 03/25/15 Tristan Lelong Senior embedded software engineer Filesystem considerations ABSTRACT The goal of this presentation is to answer a question asked by several customers: which filesystem should you use within your embedded design’s eMMC/SDCard? These storage devices use a standard block interface, compatible with traditional filesystems, but constraints are not those of desktop PC environments. EXT2/3/4, BTRFS, F2FS are the first of many solutions which come to mind, but how do they all compare? Typical queries include performance, longevity, tools availability, support, and power loss robustness. This presentation will not dive into implementation details but will instead summarize provided answers with the help of various figures and meaningful test results. 2 TABLE OF CONTENTS 1. Introduction 2. Block devices 3. Available filesystems 4. Performances 5. Tools 6. Reliability 7. Conclusion Filesystem considerations ABOUT THE AUTHOR • Tristan Lelong • Embedded software engineer @ Adeneo Embedded • French, living in the Pacific northwest • Embedded software, free software, and Linux kernel enthusiast. 4 Introduction Filesystem considerations Introduction INTRODUCTION More and more embedded designs rely on smart memory chips rather than bare NAND or NOR. This presentation will start by describing: • Some context to help understand the differences between NAND and MMC • Some typical requirements found in embedded devices designs • Potential filesystems to use on MMC devices 6 Filesystem considerations Introduction INTRODUCTION Focus will then move to block filesystems. How they are supported, what feature do they advertise. To help understand how they compare, we will present some benchmarks and comparisons regarding: • Tools • Reliability • Performances 7 Block devices Filesystem considerations Block devices MMC, EMMC, SD CARD Vocabulary: • MMC: MultiMediaCard is a memory card unveiled in 1997 by SanDisk and Siemens based on NAND flash memory. -
Implementing Nfsv4 in the Enterprise: Planning and Migration Strategies
Front cover Implementing NFSv4 in the Enterprise: Planning and Migration Strategies Planning and implementation examples for AFS and DFS migrations NFSv3 to NFSv4 migration examples NFSv4 updates in AIX 5L Version 5.3 with 5300-03 Recommended Maintenance Package Gene Curylo Richard Joltes Trishali Nayar Bob Oesterlin Aniket Patel ibm.com/redbooks International Technical Support Organization Implementing NFSv4 in the Enterprise: Planning and Migration Strategies December 2005 SG24-6657-00 Note: Before using this information and the product it supports, read the information in “Notices” on page xi. First Edition (December 2005) This edition applies to Version 5, Release 3, of IBM AIX 5L (product number 5765-G03). © Copyright International Business Machines Corporation 2005. All rights reserved. Note to U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Notices . xi Trademarks . xii Preface . xiii The team that wrote this redbook. xiv Acknowledgments . xv Become a published author . xvi Comments welcome. xvii Part 1. Introduction . 1 Chapter 1. Introduction. 3 1.1 Overview of enterprise file systems. 4 1.2 The migration landscape today . 5 1.3 Strategic and business context . 6 1.4 Why NFSv4? . 7 1.5 The rest of this book . 8 Chapter 2. Shared file system concepts and history. 11 2.1 Characteristics of enterprise file systems . 12 2.1.1 Replication . 12 2.1.2 Migration . 12 2.1.3 Federated namespace . 13 2.1.4 Caching . 13 2.2 Enterprise file system technologies. 13 2.2.1 Sun Network File System (NFS) . 13 2.2.2 Andrew File System (AFS) . -
External Flash Filesystem for Sensor Nodes with Sparse Resources
External Flash Filesystem for Sensor Nodes with sparse Resources Stephan Lehmann Stephan Rein Clemens Gühmann stephan.lehmann@tu- stephan.rein@tu- clemens.guehmann@tu- berlin.de berlin.de berlin.de Wavelet Application Group Department of Energy and Automation Technology Chair of Electronic Measurement and Diagnostic Technology Technische Universität Berlin ABSTRACT for using just a few kilobytes of RAM, the source data must This paper describes a free filesystem for external flash mem- be accessible. Another memory intensive task concerns long- ory to be employed with low-complexity sensor nodes. The term sensor logs. system uses a standard secure digital (SD) card that can be easily connected to the serial port interface (SPI) or any A cost effective solution of this memory problem could be general input/output port of the sensor’s processor. The external flash memory. Flash memory is non-volatile and filesystem is evaluated with SD- cards used in SPI mode and therefore power failure safe. Flash memory can be obtained achieves an average random write throughput of about 40 either as raw flash or as standard flash devices such as USB- kByte/sec. For random write access throughputs larger than sticks or SD- cards. Raw flashes are pure flash chips which 400 kByte/sec are achieved. The filesystem allows for stor- do not provide a controller unit for wear levelling- that is, age of large amounts of sensor or program data and can assist a technique for prolonging the service life of the erasable more memory expensive algorithms. It requires 7 kByte of storage media - or garbage collection. -
Total Defrag™ 2009
Total Defrag™ 2009 User Manual Paragon Total Defrag™ 2009 2 User Manual CONTENTS Introduction ............................................................................................................................. 3 Key Features ............................................................................................................................ 3 Installation ............................................................................................................................... 3 Minimum System Requirements ....................................................................................................................3 Installation Procedure .....................................................................................................................................4 Basic Concepts ......................................................................................................................... 5 A Hard Disk Layout.........................................................................................................................................5 File Fragmentation...........................................................................................................................................6 Defragmentation ..............................................................................................................................................7 Interface Overview.................................................................................................................. 7 General -
OEM HARD DISK DRIVE SPECIFICATIONS for DPRS
IBML S39H-4500-02 OEM HARD DISK DRIVE SPECIFICATIONS for DPRS-20810/21215 (810/1215 MB) 2.5-Inch Hard Disk Drive with SCSI Interface Revision (1.2) IBML S39H-4500-02 OEM HARD DISK DRIVE SPECIFICATIONS for DPRS-20810/21215 (810/1215 MB) 2.5-Inch Hard Disk Drive with SCSI Interface Revision (1.2) 1st Edition (ver.1.0) S39H-4500-00 (June 16, 1995) 2nd Edition (ver.1.1) S39H-4500-01 (October 24, 1995) 3rd Edition (ver.1.2) S39H-4500-02 (November 1, 1995) The following paragraph does not apply to the United Kingdom or any country where such provisions are inconsistent with local law: INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Some states do not allow disclaimer or express or implied warranties in certain transactions, therefore, this statement may not apply to You. This publication could include technical inaccuracies or typographical errors. Changes are periodically made to the information herein; these changes will be incorporated in new editions of the publication. IBM may make improve- ments and/or changes in the product(s) and/or the program(s) described in this publication at any time. It is possible that this publication may contain reference to, or information about, IBM products (machines and programs), programming, or services that are not announced in your country. Such references or information must not be construed to mean that IBM intends to announce such IBM products, programming, or services in your country. -
Learning Proxmox VE Learning Proxmox VE
Learning Proxmox VE Learning Proxmox VE Proxmox VE 4.1 provides an open source, enterprise virtualization platform on which to host virtual servers as What you will learn from this book either virtual machines or containers. Install and confi gure Proxmox VE 4.1 This book will support your practice of the requisite skills to successfully create, tailor, and deploy virtual machines Download container templates and virtual and containers with Proxmox VE 4.1. appliances Following a survey of PVE's features and characteristics, Create and host containers based on this book will contrast containers with virtual machines and templates establish cases for both. It walks through the installation Create and host virtual machines of Proxmox VE, explores the creation of containers and virtual machines, and suggests best practices for virtual Optimize virtual machine performance disk creation, network confi guration, and Proxmox VE for common use cases host and guest security. Apply the latest security patches to Throughout the book, you will navigate the Proxmox VE a Proxmox VE host Community Experience Distilled 4.1 web interface and explore options for command-line management. Contrast PVE virtual machines and containers in order to recognize their respective use cases Who this book is written for Secure Proxmox VE hosts as well as virtual This book is intended for server and system administrators machines and containers and engineers who are eager to take advantage of the Learning Proxmox VE potential of virtual machines and containers to manage Assess the benefi ts of virtualization with servers more effi ciently and make the best use of regard to budgets, server real estate, Rik Goldman resources, from energy consumption to hardware maintenance, and management time utilization and physical real estate.