Today: Distributed File Systems File System Basics
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Configuring UNIX-Specific Settings: Creating Symbolic Links : Snap
Configuring UNIX-specific settings: Creating symbolic links Snap Creator Framework NetApp September 23, 2021 This PDF was generated from https://docs.netapp.com/us-en/snap-creator- framework/installation/task_creating_symbolic_links_for_domino_plug_in_on_linux_and_solaris_hosts.ht ml on September 23, 2021. Always check docs.netapp.com for the latest. Table of Contents Configuring UNIX-specific settings: Creating symbolic links . 1 Creating symbolic links for the Domino plug-in on Linux and Solaris hosts. 1 Creating symbolic links for the Domino plug-in on AIX hosts. 2 Configuring UNIX-specific settings: Creating symbolic links If you are going to install the Snap Creator Agent on a UNIX operating system (AIX, Linux, and Solaris), for the IBM Domino plug-in to work properly, three symbolic links (symlinks) must be created to link to Domino’s shared object files. Installation procedures vary slightly depending on the operating system. Refer to the appropriate procedure for your operating system. Domino does not support the HP-UX operating system. Creating symbolic links for the Domino plug-in on Linux and Solaris hosts You need to perform this procedure if you want to create symbolic links for the Domino plug-in on Linux and Solaris hosts. You should not copy and paste commands directly from this document; errors (such as incorrectly transferred characters caused by line breaks and hard returns) might result. Copy and paste the commands into a text editor, verify the commands, and then enter them in the CLI console. The paths provided in the following steps refer to the 32-bit systems; 64-bit systems must create simlinks to /usr/lib64 instead of /usr/lib. -
IT1100 : Introduction to Operating Systems Chapter 15 What Is a Partition? What Is a Partition? Linux Partitions What Is Swap? M
IT1100 : Introduction to Operating Systems Chapter 15 What is a partition? A partition is just a logical division of your hard drive. This is done to put data in different locations for flexibility, scalability, ease of administration, and a variety of other reasons. One reason might be so you can install Linux and Windows side-by-side. What is a partition? Another reason is to encapsulate your data. Keeping your system files and user files separate can protect one or the otherfrom malware. Since file system corruption is local to a partition, you stand to lose only some of your data if an accident occurs. Upgrading and/or reformatting is easier when your personal files are stored on a separate partition. Limit data growth. Runaway processes or maniacal users can consume so much disk space that the operating system no longer has room on the hard drive for its bookkeeping operations. This will lead to disaster. By segregating space, you ensure that things other than the operating system die when allocated disk space is exhausted. Linux Partitions In Linux, a minimum of 1 partition is required for the / . Mounting is the action of connecting a filesystem/partition to a particular point in the / root filesystem. I.e. When a usb stick is inserted, it is assigned a particular mount point and is available to the filesytem tree. - In windows you might have an A:, or B:, or C:, all of which point to different filesystems. What is Swap? If RAM fills up, by running too many processes or a process with a memory leak, new processes will fail if your system doesn’t have a way to extend system 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. -
File Formats
man pages section 4: File Formats Sun Microsystems, Inc. 4150 Network Circle Santa Clara, CA 95054 U.S.A. Part No: 817–3945–10 September 2004 Copyright 2004 Sun Microsystems, Inc. 4150 Network Circle, Santa Clara, CA 95054 U.S.A. All rights reserved. This product or document is protected by copyright and distributed under licenses restricting its use, copying, distribution, and decompilation. No part of this product or document may be reproduced in any form by any means without prior written authorization of Sun and its licensors, if any. Third-party software, including font technology, is copyrighted and licensed from Sun suppliers. Parts of the product may be derived from Berkeley BSD systems, licensed from the University of California. UNIX is a registered trademark in the U.S. and other countries, exclusively licensed through X/Open Company, Ltd. Sun, Sun Microsystems, the Sun logo, docs.sun.com, AnswerBook, AnswerBook2, and Solaris are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and other countries. All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International, Inc. in the U.S. and other countries. Products bearing SPARC trademarks are based upon an architecture developed by Sun Microsystems, Inc. The OPEN LOOK and Sun™ Graphical User Interface was developed by Sun Microsystems, Inc. for its users and licensees. Sun acknowledges the pioneering efforts of Xerox in researching and developing the concept of visual or graphical user interfaces for the computer industry. Sun holds a non-exclusive license from Xerox to the Xerox Graphical User Interface, which license also covers Sun’s licensees who implement OPEN LOOK GUIs and otherwise comply with Sun’s written license agreements. -
Where Do You Want to Go Today? Escalating
Where Do You Want to Go Today? ∗ Escalating Privileges by Pathname Manipulation Suresh Chari Shai Halevi Wietse Venema IBM T.J. Watson Research Center, Hawthorne, New York, USA Abstract 1. Introduction We analyze filename-based privilege escalation attacks, In this work we take another look at the problem of where an attacker creates filesystem links, thereby “trick- privilege escalation via manipulation of filesystem names. ing” a victim program into opening unintended files. Historically, attention has focused on attacks against priv- We develop primitives for a POSIX environment, provid- ileged processes that open files in directories that are ing assurance that files in “safe directories” (such as writable by an attacker. One classical example is email /etc/passwd) cannot be opened by looking up a file by delivery in the UNIX environment (e.g., [9]). Here, an “unsafe pathname” (such as a pathname that resolves the mail-delivery directory (e.g., /var/mail) is often through a symbolic link in a world-writable directory). In group or world writable. An adversarial user may use today's UNIX systems, solutions to this problem are typ- its write permission to create a hard link or symlink at ically built into (some) applications and use application- /var/mail/root that resolves to /etc/passwd. A specific knowledge about (un)safety of certain directories. simple-minded mail-delivery program that appends mail to In contrast, we seek solutions that can be implemented in the file /var/mail/root can have disastrous implica- the filesystem itself (or a library on top of it), thus providing tions for system security. -
![[13주차] Sysfs and Procfs](https://docslib.b-cdn.net/cover/8218/13-sysfs-and-procfs-338218.webp)
[13주차] Sysfs and Procfs
1 7 Computer Core Practice1: Operating System Week13. sysfs and procfs Jhuyeong Jhin and Injung Hwang Embedded Software Lab. Embedded Software Lab. 2 sysfs 7 • A pseudo file system provided by the Linux kernel. • sysfs exports information about various kernel subsystems, HW devices, and associated device drivers to user space through virtual files. • The mount point of sysfs is usually /sys. • sysfs abstrains devices or kernel subsystems as a kobject. Embedded Software Lab. 3 How to create a file in /sys 7 1. Create and add kobject to the sysfs 2. Declare a variable and struct kobj_attribute – When you declare the kobj_attribute, you should implement the functions “show” and “store” for reading and writing from/to the variable. – One variable is one attribute 3. Create a directory in the sysfs – The directory have attributes as files • When the creation of the directory is completed, the directory and files(attributes) appear in /sys. • Reference: ${KERNEL_SRC_DIR}/include/linux/sysfs.h ${KERNEL_SRC_DIR}/fs/sysfs/* • Example : ${KERNEL_SRC_DIR}/kernel/ksysfs.c Embedded Software Lab. 4 procfs 7 • A special filesystem in Unix-like operating systems. • procfs presents information about processes and other system information in a hierarchical file-like structure. • Typically, it is mapped to a mount point named /proc at boot time. • procfs acts as an interface to internal data structures in the kernel. The process IDs of all processes in the system • Kernel provides a set of functions which are designed to make the operations for the file in /proc : “seq_file interface”. – We will create a file in procfs and print some data from data structure by using this interface. -
File Permissions Do Not Restrict Root
Filesystem Security 1 General Principles • Files and folders are managed • A file handle provides an by the operating system opaque identifier for a • Applications, including shells, file/folder access files through an API • File operations • Access control entry (ACE) – Open file: returns file handle – Allow/deny a certain type of – Read/write/execute file access to a file/folder by – Close file: invalidates file user/group handle • Access control list (ACL) • Hierarchical file organization – Collection of ACEs for a – Tree (Windows) file/folder – DAG (Linux) 2 Discretionary Access Control (DAC) • Users can protect what they own – The owner may grant access to others – The owner may define the type of access (read/write/execute) given to others • DAC is the standard model used in operating systems • Mandatory Access Control (MAC) – Alternative model not covered in this lecture – Multiple levels of security for users and documents – Read down and write up principles 3 Closed vs. Open Policy Closed policy Open Policy – Also called “default secure” • Deny Tom read access to “foo” • Give Tom read access to “foo” • Deny Bob r/w access to “bar” • Give Bob r/w access to “bar • Tom: I would like to read “foo” • Tom: I would like to read “foo” – Access denied – Access allowed • Tom: I would like to read “bar” • Tom: I would like to read “bar” – Access allowed – Access denied 4 Closed Policy with Negative Authorizations and Deny Priority • Give Tom r/w access to “bar” • Deny Tom write access to “bar” • Tom: I would like to read “bar” – Access -
21Files2.Pdf
Here is a portion of a Unix directory tree. The ovals represent files, the rectangles represent directories (which are really just special cases of files). A simple implementation of a directory consists of an array of pairs of component name and inode number, where the latter identifies the target file’s inode to the operating system (an inode is data structure maintained by the operating system that represents a file). Note that every directory contains two special entries, “.” and “..”. The former refers to the directory itself, the latter to the directory’s parent (in the case of the slide, the directory is the root directory and has no parent, thus its “..” entry is a special case that refers to the directory itself). While this implementation of a directory was used in early file systems for Unix, it suffers from a number of practical problems (for example, it doesn’t scale well for large directories). It provides a good model for the semantics of directory operations, but directory implementations on modern systems are more complicated than this (and are beyond the scope of this course). Here are two directory entries referring to the same file. This is done, via the shell, through the ln command which creates a (hard) link to its first argument, giving it the name specified by its second argument. The shell’s “ln” command is implemented using the link system call. Here are the (abbreviated) contents of both the root (/) and /etc directories, showing how /unix and /etc/image are the same file. Note that if the directory entry /unix is deleted (via the shell’s “rm” command), the file (represented by inode 117) continues to exist, since there is still a directory entry referring to it. -
Refs: Is It a Game Changer? Presented By: Rick Vanover, Director, Technical Product Marketing & Evangelism, Veeam
Technical Brief ReFS: Is It a Game Changer? Presented by: Rick Vanover, Director, Technical Product Marketing & Evangelism, Veeam Sponsored by ReFS: Is It a Game Changer? OVERVIEW Backing up data is more important than ever, as data centers store larger volumes of information and organizations face various threats such as ransomware and other digital risks. Microsoft’s Resilient File System or ReFS offers a more robust solution than the old NT File System. In fact, Microsoft has stated that ReFS is the preferred data volume for Windows Server 2016. ReFS is an ideal solution for backup storage. By utilizing the ReFS BlockClone API, Veeam has developed Fast Clone, a fast, efficient storage backup solution. This solution offers organizations peace of mind through a more advanced approach to synthetic full backups. CONTEXT Rick Vanover discussed Microsoft’s Resilient File System (ReFS) and described how Veeam leverages this technology for its Fast Clone backup functionality. KEY TAKEAWAYS Resilient File System is a Microsoft storage technology that can transform the data center. Resilient File System or ReFS is a valuable Microsoft storage technology for data centers. Some of the key differences between ReFS and the NT File System (NTFS) are: ReFS provides many of the same limits as NTFS, but supports a larger maximum volume size. ReFS and NTFS support the same maximum file name length, maximum path name length, and maximum file size. However, ReFS can handle a maximum volume size of 4.7 zettabytes, compared to NTFS which can only support 256 terabytes. The most common functions are available on both ReFS and NTFS. -
Oracle® Linux 7 Managing File Systems
Oracle® Linux 7 Managing File Systems F32760-07 August 2021 Oracle Legal Notices Copyright © 2020, 2021, Oracle and/or its affiliates. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing. If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, then the following notice is applicable: U.S. GOVERNMENT END USERS: Oracle programs (including any operating system, integrated software, any programs embedded, installed or activated on delivered hardware, and modifications of such programs) and Oracle computer documentation or other Oracle data delivered to or accessed by U.S. Government end users are "commercial computer software" or "commercial computer software documentation" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, reproduction, duplication, release, display, disclosure, modification, preparation of derivative works, and/or adaptation of i) Oracle programs (including any operating system, integrated software, any programs embedded, installed or activated on delivered hardware, and modifications of such programs), ii) Oracle computer documentation and/or iii) other Oracle data, is subject to the rights and limitations specified in the license contained in the applicable contract. -
File Management Virtual File System: Interface, Data Structures
File management Virtual file system: interface, data structures Table of contents • Virtual File System (VFS) • File system interface Motto – Creating and opening a file – Reading from a file Everything is a file – Writing to a file – Closing a file • VFS data structures – Process data structures with file information – Structure fs_struct – Structure files_struct – Structure file – Inode – Superblock • Pipe vs FIFO 2 Virtual File System (VFS) VFS (source: Tizen Wiki) 3 Virtual File System (VFS) Linux can support many different (formats of) file systems. (How many?) The virtual file system uses a unified interface when accessing data in various formats, so that from the user level adding support for the new data format is relatively simple. This concept allows implementing support for data formats – saved on physical media (Ext2, Ext3, Ext4 from Linux, VFAT, NTFS from Microsoft), – available via network (like NFS), – dynamically created at the user's request (like /proc). This unified interface is fully compatible with the Unix-specific file model, making it easier to implement native Linux file systems. 4 File System Interface In Linux, processes refer to files using a well-defined set of system functions: – functions that support existing files: open(), read(), write(), lseek() and close(), – functions for creating new files: creat(), – functions used when implementing pipes: pipe() i dup(). The first step that the process must take to access the data of an existing file is to call the open() function. If successful, it passes the file descriptor to the process, which it can use to perform other operations on the file, such as reading (read()) and writing (write()). -
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.