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MLNX OFED Documentation Rev 5.0-2.1.8.0
MLNX_OFED Documentation Rev 5.0-2.1.8.0 Exported on May/21/2020 06:13 AM https://docs.mellanox.com/x/JLV-AQ Notice This document is provided for information purposes only and shall not be regarded as a warranty of a certain functionality, condition, or quality of a product. NVIDIA Corporation (“NVIDIA”) makes no representations or warranties, expressed or implied, as to the accuracy or completeness of the information contained in this document and assumes no responsibility for any errors contained herein. NVIDIA shall have no liability for the consequences or use of such information or for any infringement of patents or other rights of third parties that may result from its use. This document is not a commitment to develop, release, or deliver any Material (defined below), code, or functionality. NVIDIA reserves the right to make corrections, modifications, enhancements, improvements, and any other changes to this document, at any time without notice. Customer should obtain the latest relevant information before placing orders and should verify that such information is current and complete. NVIDIA products are sold subject to the NVIDIA standard terms and conditions of sale supplied at the time of order acknowledgement, unless otherwise agreed in an individual sales agreement signed by authorized representatives of NVIDIA and customer (“Terms of Sale”). NVIDIA hereby expressly objects to applying any customer general terms and conditions with regards to the purchase of the NVIDIA product referenced in this document. No contractual obligations are formed either directly or indirectly by this document. NVIDIA products are not designed, authorized, or warranted to be suitable for use in medical, military, aircraft, space, or life support equipment, nor in applications where failure or malfunction of the NVIDIA product can reasonably be expected to result in personal injury, death, or property or environmental damage. -
Study of File System Evolution
Study of File System Evolution Swaminathan Sundararaman, Sriram Subramanian Department of Computer Science University of Wisconsin {swami, srirams} @cs.wisc.edu Abstract File systems have traditionally been a major area of file systems are typically developed and maintained by research and development. This is evident from the several programmer across the globe. At any point in existence of over 50 file systems of varying popularity time, for a file system, there are three to six active in the current version of the Linux kernel. They developers, ten to fifteen patch contributors but a single represent a complex subsystem of the kernel, with each maintainer. These people communicate through file system employing different strategies for tackling individual file system mailing lists [14, 16, 18] various issues. Although there are many file systems in submitting proposals for new features, enhancements, Linux, there has been no prior work (to the best of our reporting bugs, submitting and reviewing patches for knowledge) on understanding how file systems evolve. known bugs. The problems with the open source We believe that such information would be useful to the development approach is that all communication is file system community allowing developers to learn buried in the mailing list archives and aren’t easily from previous experiences. accessible to others. As a result when new file systems are developed they do not leverage past experience and This paper looks at six file systems (Ext2, Ext3, Ext4, could end up re-inventing the wheel. To make things JFS, ReiserFS, and XFS) from a historical perspective worse, people could typically end up doing the same (between kernel versions 1.0 to 2.6) to get an insight on mistakes as done in other file systems. -
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. -
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. -
How to Create a Custom Live CD for Secure Remote Incident Handling in the Enterprise
How to Create a Custom Live CD for Secure Remote Incident Handling in the Enterprise Abstract This paper will document a process to create a custom Live CD for secure remote incident handling on Windows and Linux systems. The process will include how to configure SSH for remote access to the Live CD even when running behind a NAT device. The combination of customization and secure remote access will make this process valuable to incident handlers working in enterprise environments with limited remote IT support. Bert Hayes, [email protected] How to Create a Custom Live CD for Remote Incident Handling 2 Table of Contents Abstract ...........................................................................................................................................1 1. Introduction ............................................................................................................................5 2. Making Your Own Customized Debian GNU/Linux Based System........................................7 2.1. The Development Environment ......................................................................................7 2.2. Making Your Dream Incident Handling System...............................................................9 2.3. Hardening the Base Install.............................................................................................11 2.3.1. Managing Root Access with Sudo..........................................................................11 2.4. Randomizing the Handler Password at Boot Time ........................................................12 -
Open Source Licensing Information for Cisco IP Phone 8800 Series
Open Source Used In Cisco IP Phone 8800 Series 12.1(1) Cisco Systems, Inc. www.cisco.com Cisco has more than 200 offices worldwide. Addresses, phone numbers, and fax numbers are listed on the Cisco website at www.cisco.com/go/offices. Text Part Number: 78EE117C99-163803748 Open Source Used In Cisco IP Phone 8800 Series 12.1(1) 1 This document contains licenses and notices for open source software used in this product. With respect to the free/open source software listed in this document, if you have any questions or wish to receive a copy of any source code to which you may be entitled under the applicable free/open source license(s) (such as the GNU Lesser/General Public License), please contact us at [email protected]. In your requests please include the following reference number 78EE117C99-163803748 Contents 1.1 bluez 4.101 :MxC-1.1C R4.0 1.1.1 Available under license 1.2 BOOST C++ Library 1.63.0 1.2.1 Available under license 1.3 busybox 1.21.0 1.3.1 Available under license 1.4 Busybox 1.23.1 1.4.1 Available under license 1.5 cjose 0.4.1 1.5.1 Available under license 1.6 cppformat 2.0.0 1.6.1 Available under license 1.7 curl 7.26.0 1.7.1 Available under license 1.8 dbus 1.4.1 :MxC-1.1C R4.0 1.8.1 Available under license 1.9 DirectFB library and utilities 1.4.5 1.9.1 Available under license 1.10 dnsmasq 2.46 1.10.1 Available under license 1.11 flite 2.0.0 1.11.1 Available under license 1.12 glibc 2.13 1.12.1 Available under license 1.13 hostapd 2.0 :MxC-1.1C R4.0 1.13.1 Available under license Open Source Used -
In Search of the Ideal Storage Configuration for Docker Containers
In Search of the Ideal Storage Configuration for Docker Containers Vasily Tarasov1, Lukas Rupprecht1, Dimitris Skourtis1, Amit Warke1, Dean Hildebrand1 Mohamed Mohamed1, Nagapramod Mandagere1, Wenji Li2, Raju Rangaswami3, Ming Zhao2 1IBM Research—Almaden 2Arizona State University 3Florida International University Abstract—Containers are a widely successful technology today every running container. This would cause a great burden on popularized by Docker. Containers improve system utilization by the I/O subsystem and make container start time unacceptably increasing workload density. Docker containers enable seamless high for many workloads. As a result, copy-on-write (CoW) deployment of workloads across development, test, and produc- tion environments. Docker’s unique approach to data manage- storage and storage snapshots are popularly used and images ment, which involves frequent snapshot creation and removal, are structured in layers. A layer consists of a set of files and presents a new set of exciting challenges for storage systems. At layers with the same content can be shared across images, the same time, storage management for Docker containers has reducing the amount of storage required to run containers. remained largely unexplored with a dizzying array of solution With Docker, one can choose Aufs [6], Overlay2 [7], choices and configuration options. In this paper we unravel the multi-faceted nature of Docker storage and demonstrate its Btrfs [8], or device-mapper (dm) [9] as storage drivers which impact on system and workload performance. As we uncover provide the required snapshotting and CoW capabilities for new properties of the popular Docker storage drivers, this is a images. None of these solutions, however, were designed with sobering reminder that widespread use of new technologies can Docker in mind and their effectiveness for Docker has not been often precede their careful evaluation. -
Chapter 19 RECOVERING DIGITAL EVIDENCE from LINUX SYSTEMS
Chapter 19 RECOVERING DIGITAL EVIDENCE FROM LINUX SYSTEMS Philip Craiger Abstract As Linux-kernel-based operating systems proliferate there will be an in evitable increase in Linux systems that law enforcement agents must process in criminal investigations. The skills and expertise required to recover evidence from Microsoft-Windows-based systems do not neces sarily translate to Linux systems. This paper discusses digital forensic procedures for recovering evidence from Linux systems. In particular, it presents methods for identifying and recovering deleted files from disk and volatile memory, identifying notable and Trojan files, finding hidden files, and finding files with renamed extensions. All the procedures are accomplished using Linux command line utilities and require no special or commercial tools. Keywords: Digital evidence, Linux system forensics !• Introduction Linux systems will be increasingly encountered at crime scenes as Linux increases in popularity, particularly as the OS of choice for servers. The skills and expertise required to recover evidence from a Microsoft- Windows-based system, however, do not necessarily translate to the same tasks on a Linux system. For instance, the Microsoft NTFS, FAT, and Linux EXT2/3 file systems work differently enough that under standing one tells httle about how the other functions. In this paper we demonstrate digital forensics procedures for Linux systems using Linux command line utilities. The ability to gather evidence from a running system is particularly important as evidence in RAM may be lost if a forensics first responder does not prioritize the collection of live evidence. The forensic procedures discussed include methods for identifying and recovering deleted files from RAM and magnetic media, identifying no- 234 ADVANCES IN DIGITAL FORENSICS tables files and Trojans, and finding hidden files and renamed files (files with renamed extensions. -
De-Anonymizing Live Cds Through Physical Memory Analysis
De-Anonymizing Live CDs through Physical Memory Analysis Andrew Case [email protected] Digital Forensics Solutions Abstract Traditional digital forensics encompasses the examination of data from an offline or “dead” source such as a disk image. Since the filesystem is intact on these images, a number of forensics techniques are available for analysis such as file and metadata examination, timelining, deleted file recovery, indexing, and searching. Live CDs present a serious problem for this investigative model, however, since the OS and applications execute in a RAM-only environment and do not save data on non-volatile storage devices such as the local disk. In order to solve this problem, we present a number of techniques that support complete recovery of a live CD’s in-memory filesystem and partial recovery of its deleted contents. We also present memory analysis of the popular Tor application, since it is used by a number of live CDs in an attempt to keep network communications encrypted and anonymous. 1 Introduction Traditional digital forensics encompasses the examination of data from an offline or “dead” source such as a disk image. Under normal circumstances, evidence is obtained by first creating an exact, bit-for-bit copy of the target disk, followed by hashing of both the target disk and the new copy. If these hashes match then it is known that an exact copy has been made, and the hash is recorded to later prove that evidence was not modified during the investigation. Besides satisfying legal requirements, obtaining a bit-for-bit copy of data provides investigators with a wealth of information to examine and makes available a number of forensics techniques. -
Understanding the Performance of Container Execution Environments
Understanding the performance of container execution environments Guillaume Everarts de Velp, Etienne Rivière and Ramin Sadre [email protected] EPL, ICTEAM, UCLouvain, Belgium Abstract example is an automatic grading platform named INGIn- Many application server backends leverage container tech- ious [2, 3]. This platform is used extensively at UCLouvain nologies to support workloads formed of short-lived, but and other institutions around the world to provide computer potentially I/O-intensive, operations. The latency at which science and engineering students with automated feedback container-supported operations complete impacts both the on programming assignments, through the execution of se- users’ experience and the throughput that the platform can ries of unit tests prepared by instructors. It is necessary that achieve. This latency is a result of both the bootstrap and the student code and the testing runtime run in isolation from execution time of the containers and is impacted greatly by each others. Containers answer this need perfectly: They the performance of the I/O subsystem. Configuring appro- allow students’ code to run in a controlled and reproducible priately the container environment and technology stack environment while reducing risks related to ill-behaved or to obtain good performance is not an easy task, due to the even malicious code. variety of options, and poor visibility on their interactions. Service latency is often the most important criteria for We present in this paper a benchmarking tool for the selecting a container execution environment. Slow response multi-parametric study of container bootstrap time and I/O times can impair the usability of an edge computing infras- performance, allowing us to understand such interactions tructure, or result in students frustration in the case of IN- within a controlled environment. -
Hardware-Driven Evolution in Storage Software by Zev Weiss A
Hardware-Driven Evolution in Storage Software by Zev Weiss A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Computer Sciences) at the UNIVERSITY OF WISCONSIN–MADISON 2018 Date of final oral examination: June 8, 2018 ii The dissertation is approved by the following members of the Final Oral Committee: Andrea C. Arpaci-Dusseau, Professor, Computer Sciences Remzi H. Arpaci-Dusseau, Professor, Computer Sciences Michael M. Swift, Professor, Computer Sciences Karthikeyan Sankaralingam, Professor, Computer Sciences Johannes Wallmann, Associate Professor, Mead Witter School of Music i © Copyright by Zev Weiss 2018 All Rights Reserved ii To my parents, for their endless support, and my cousin Charlie, one of the kindest people I’ve ever known. iii Acknowledgments I have taken what might be politely called a “scenic route” of sorts through grad school. While Ph.D. students more focused on a rapid graduation turnaround time might find this regrettable, I am glad to have done so, in part because it has afforded me the opportunities to meet and work with so many excellent people along the way. I owe debts of gratitude to a large cast of characters: To my advisors, Andrea and Remzi Arpaci-Dusseau. It is one of the most common pieces of wisdom imparted on incoming grad students that one’s relationship with one’s advisor (or advisors) is perhaps the single most important factor in whether these years of your life will be pleasant or unpleasant, and I feel exceptionally fortunate to have ended up iv with the advisors that I’ve had.