Persistent 9P Sessions for Plan 9
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Venti Analysis and Memventi Implementation
Master’s thesis Venti analysis and memventi implementation Designing a trace-based simulator and implementing a venti with in-memory index Mechiel Lukkien [email protected] August 8, 2007 Committee: Faculty of EEMCS prof. dr. Sape J. Mullender DIES, Distributed and Embedded Systems ir. J. Scholten University of Twente ir. P.G. Jansen Enschede, The Netherlands 2 Abstract [The next page has a Dutch summary] Venti is a write-once content-addressed archival storage system, storing its data on magnetic disks: each data block is addressed by its 20-byte SHA-1 hash (called score). This project initially aimed to design and implement a trace-based simula- tor matching Venti behaviour closely enough to be able to use it to determine good configuration parameters (such as cache sizes), and for testing new opti- misations. A simplistic simulator has been implemented, but it does not model Venti behaviour accurately enough for its intended goal, nor is it polished enough for use. Modelled behaviour is inaccurate because the advanced optimisations of Venti have not been implemented in the simulator. However, implementation suggestions for these optimisations are presented. In the process of designing the simulator, the Venti source code has been investigated, the optimisations have been documented, and disk and Venti per- formance have been measured. This allowed for recommendations about per- formance, even without a simulator. Beside magnetic disks, also flash memory and the upcoming mems-based storage devices have been investigated for use with Venti; they may be usable in the near future, but require explicit support. The focus of this project has shifted towards designing and implementing memventi, an alternative implementation of the venti protocol. -
Protocols: 0-9, A
Protocols: 0-9, A • 3COM-AMP3, on page 4 • 3COM-TSMUX, on page 5 • 3PC, on page 6 • 4CHAN, on page 7 • 58-CITY, on page 8 • 914C G, on page 9 • 9PFS, on page 10 • ABC-NEWS, on page 11 • ACAP, on page 12 • ACAS, on page 13 • ACCESSBUILDER, on page 14 • ACCESSNETWORK, on page 15 • ACCUWEATHER, on page 16 • ACP, on page 17 • ACR-NEMA, on page 18 • ACTIVE-DIRECTORY, on page 19 • ACTIVESYNC, on page 20 • ADCASH, on page 21 • ADDTHIS, on page 22 • ADOBE-CONNECT, on page 23 • ADWEEK, on page 24 • AED-512, on page 25 • AFPOVERTCP, on page 26 • AGENTX, on page 27 • AIRBNB, on page 28 • AIRPLAY, on page 29 • ALIWANGWANG, on page 30 • ALLRECIPES, on page 31 • ALPES, on page 32 • AMANDA, on page 33 • AMAZON, on page 34 • AMEBA, on page 35 • AMAZON-INSTANT-VIDEO, on page 36 Protocols: 0-9, A 1 Protocols: 0-9, A • AMAZON-WEB-SERVICES, on page 37 • AMERICAN-EXPRESS, on page 38 • AMINET, on page 39 • AN, on page 40 • ANCESTRY-COM, on page 41 • ANDROID-UPDATES, on page 42 • ANET, on page 43 • ANSANOTIFY, on page 44 • ANSATRADER, on page 45 • ANY-HOST-INTERNAL, on page 46 • AODV, on page 47 • AOL-MESSENGER, on page 48 • AOL-MESSENGER-AUDIO, on page 49 • AOL-MESSENGER-FT, on page 50 • AOL-MESSENGER-VIDEO, on page 51 • AOL-PROTOCOL, on page 52 • APC-POWERCHUTE, on page 53 • APERTUS-LDP, on page 54 • APPLEJUICE, on page 55 • APPLE-APP-STORE, on page 56 • APPLE-IOS-UPDATES, on page 57 • APPLE-REMOTE-DESKTOP, on page 58 • APPLE-SERVICES, on page 59 • APPLE-TV-UPDATES, on page 60 • APPLEQTC, on page 61 • APPLEQTCSRVR, on page 62 • APPLIX, on page 63 • ARCISDMS, -
Persistent 9P Sessions for Plan 9
Persistent 9P Sessions for Plan 9 Gorka Guardiola, [email protected] Russ Cox, [email protected] Eric Van Hensbergen, [email protected] ABSTRACT Traditionally, Plan 9 [5] runs mainly on local networks, where lost connections are rare. As a result, most programs, including the kernel, do not bother to plan for their file server connections to fail. These programs must be restarted when a connection does fail. If the kernel’s connection to the root file server fails, the machine must be rebooted. This approach suffices only because lost connections are rare. Across long distance networks, where connection failures are more common, it becomes woefully inadequate. To address this problem, we wrote a program called recover, which proxies a 9P session on behalf of a client and takes care of redialing the remote server and reestablishing con- nection state as necessary, hiding network failures from the client. This paper presents the design and implementation of recover, along with performance benchmarks on Plan 9 and on Linux. 1. Introduction Plan 9 is a distributed system developed at Bell Labs [5]. Resources in Plan 9 are presented as synthetic file systems served to clients via 9P, a simple file protocol. Unlike file protocols such as NFS, 9P is stateful: per-connection state such as which files are opened by which clients is maintained by servers. Maintaining per-connection state allows 9P to be used for resources with sophisticated access control poli- cies, such as exclusive-use lock files and chat session multiplexers. It also makes servers easier to imple- ment, since they can forget about file ids once a connection is lost. -
Virtfs—A Virtualization Aware File System Pass-Through
VirtFS—A virtualization aware File System pass-through Venkateswararao Jujjuri Eric Van Hensbergen Anthony Liguori IBM Linux Technology Center IBM Research Austin IBM Linux Technology Center [email protected] [email protected] [email protected] Badari Pulavarty IBM Linux Technology Center [email protected] Abstract operations into block device operations and then again into host file system operations. This paper describes the design and implementation of In addition to performance improvements over a tradi- a paravirtualized file system interface for Linux in the tional virtual block device, exposing guest file system KVM environment. Today’s solution of sharing host activity to the hypervisor provides greater insight to the files on the guest through generic network file systems hypervisor about the workload the guest is running. This like NFS and CIFS suffer from major performance and allows the hypervisor to make more intelligent decisions feature deficiencies as these protocols are not designed with respect to I/O caching and creates new opportuni- or optimized for virtualization. To address the needs of ties for hypervisor-based services like de-duplification. the virtualization paradigm, in this paper we are intro- ducing a new paravirtualized file system called VirtFS. In Section 2 of this paper, we explore more details about This new file system is currently under development and the motivating factors for paravirtualizing the file sys- is being built using QEMU, KVM, VirtIO technologies tem layer. In Section 3, we introduce the VirtFS design and 9P2000.L protocol. including an overview of the 9P protocol, which VirtFS is based on, along with a set of extensions introduced for greater Linux guest compatibility. -
Looking to the Future by JOHN BALDWIN
1 of 3 Looking to the Future BY JOHN BALDWIN FreeBSD’s 13.0 release delivers new features to users and refines the workflow for new contri- butions. FreeBSD contributors have been busy fixing bugs and adding new features since 12.0’s release in December of 2018. In addition, FreeBSD developers have refined their vision to focus on FreeBSD’s future users. An abbreviated list of some of the changes in 13.0 is given below. A more detailed list can be found in the release notes. Shifting Tools Not all of the changes in the FreeBSD Project over the last two years have taken the form of patches. Some of the largest changes have been made in the tools used to contribute to FreeBSD. The first major change is that FreeBSD has switched from Subversion to Git for storing source code, documentation, and ports. Git is widely used in the software industry and is more familiar to new contribu- tors than Subversion. Git’s distributed nature also more easily facilitates contributions from individuals who are Not all of the changes in the not committers. FreeBSD had been providing Git mir- rors of the Subversion repositories for several years, and FreeBSD Project over the last many developers had used Git to manage in-progress patches. The Git mirrors have now become the offi- two years have taken the form cial repositories and changes are now pushed directly of patches. to Git instead of Subversion. FreeBSD 13.0 is the first release whose sources are only available via Git rather than Subversion. -
Plan 9 from Bell Labs
Plan 9 from Bell Labs “UNIX++ Anyone?” Anant Narayanan Malaviya National Institute of Technology FOSS.IN 2007 What is it? Advanced technology transferred via mind-control from aliens in outer space Humans are not expected to understand it (Due apologies to lisperati.com) Yeah Right • More realistically, a distributed operating system • Designed by the creators of C, UNIX, AWK, UTF-8, TROFF etc. etc. • Widely acknowledged as UNIX’s true successor • Distributed under terms of the Lucent Public License, which appears on the OSI’s list of approved licenses, also considered free software by the FSF What For? “Not only is UNIX dead, it’s starting to smell really bad.” -- Rob Pike (circa 1991) • UNIX was a fantastic idea... • ...in it’s time - 1970’s • Designed primarily as a “time-sharing” system, before the PC era A closer look at Unix TODAY It Works! But that doesn’t mean we don’t develop superior alternates GNU/Linux • GNU’s not UNIX, but it is! • Linux was inspired by Minix, which was in turn inspired by UNIX • GNU/Linux (mostly) conforms to ANSI and POSIX requirements • GNU/Linux, on the desktop, is playing “catch-up” with Windows or Mac OS X, offering little in terms of technological innovation Ok, and... • Most of the “modern ideas” we use today were “bolted” on an ancient underlying system • Don’t believe me? A “modern” UNIX Terminal Where did it go wrong? • Early UNIX, “everything is a file” • Brilliant! • Only until people started adding “features” to the system... Why you shouldn’t be working with GNU/Linux • The Socket API • POSIX • X11 • The Bindings “rat-race” • 300 system calls and counting.. -
Virtualization Best Practices
SUSE Linux Enterprise Server 15 SP1 Virtualization Best Practices SUSE Linux Enterprise Server 15 SP1 Publication Date: September 24, 2021 Contents 1 Virtualization Scenarios 2 2 Before You Apply Modifications 2 3 Recommendations 3 4 VM Host Server Configuration and Resource Allocation 3 5 VM Guest Images 25 6 VM Guest Configuration 36 7 VM Guest-Specific Configurations and Settings 42 8 Xen: Converting a Paravirtual (PV) Guest to a Fully Virtual (FV/HVM) Guest 45 9 External References 49 1 SLES 15 SP1 1 Virtualization Scenarios Virtualization oers a lot of capabilities to your environment. It can be used in multiple scenarios. To get more details about it, refer to the Book “Virtualization Guide” and in particular, to the following sections: Book “Virtualization Guide”, Chapter 1 “Virtualization Technology”, Section 1.2 “Virtualization Capabilities” Book “Virtualization Guide”, Chapter 1 “Virtualization Technology”, Section 1.3 “Virtualization Benefits” This best practice guide will provide advice for making the right choice in your environment. It will recommend or discourage the usage of options depending on your workload. Fixing conguration issues and performing tuning tasks will increase the performance of VM Guest's near to bare metal. 2 Before You Apply Modifications 2.1 Back Up First Changing the conguration of the VM Guest or the VM Host Server can lead to data loss or an unstable state. It is really important that you do backups of les, data, images, etc. before making any changes. Without backups you cannot restore the original state after a data loss or a misconguration. Do not perform tests or experiments on production systems. -
ZFS: Love Your Data
ZFS: Love Your Data Neal H. Waleld LinuxCon Europe, 14 October 2014 ZFS Features I Security I End-to-End consistency via checksums I Self Healing I Copy on Write Transactions I Additional copies of important data I Snapshots and Clones I Simple, Incremental Remote Replication I Easier Administration I One shared pool rather than many statically-sized volumes I Performance Improvements I Hierarchical Storage Management (HSM) I Pooled Architecture =) shared IOPs I Developed for many-core systems I Scalable 128 I Pool Address Space: 2 bytes I O(1) operations I Fine-grained locks I On-disk data is protected by ECC I But, doesn't correct / catch all errors Silent Data Corruption I Data errors that are not caught by hard drive I = Read returns dierent data from what was written Silent Data Corruption I Data errors that are not caught by hard drive I = Read returns dierent data from what was written I On-disk data is protected by ECC I But, doesn't correct / catch all errors Uncorrectable Errors By Cory Doctorow, CC BY-SA 2.0 I Reported as BER (Bit Error Rate) I According to Data Sheets: 14 I Desktop: 1 corrupted bit per 10 (12 TB) 15 I Enterprise: 1 corrupted bit per 10 (120 TB) ∗ I Practice: 1 corrupted sector per 8 to 20 TB ∗Je Bonwick and Bill Moore, ZFS: The Last Word in File Systems, 2008 Types of Errors I Bit Rot I Phantom writes I Misdirected read / write 8 9 y I 1 per 10 to 10 IOs I = 1 error per 50 to 500 GB (assuming 512 byte IOs) I DMA Parity Errors By abdallahh, CC BY-SA 2.0 I Software / Firmware Bugs I Administration Errors yUlrich -
(Brief) 2. an Extensible Compiler for Systems Programming
Show and Tell 1. Plan 9 Things (brief) 2. An Extensible Compiler for Systems Programming Russ Cox rsc@plan9 1127 Show and Tell April 19, 2005 who am i ................................................................................................................. ‘‘Neighborhood kid’’ 1995 summer hacking Excel (jlb) 1995-1997 cable modems (nls, tom) 1997-1999 annoying Plan 9 user 1999 summer doing Plan 9 graphics (rob, jmk) 1999-present assorted Plan 9 hacking Plan 9 Things ........................................................................................................ VBE ߝ use BIOS to set up VGA modes ߝ requires switching into real mode and back Venti ߝ reworked significantly ߝ aggressive caching, prefetching, batching, delayed writes ߝ Bloom filter to avoid index misses Plan 9 from User Space (plan9port) ߝ port bulk of Plan 9 software to Unix systems ߝ Linux, FreeBSD, NetBSD, SunOS, Mac OS X .................................................................................................................................... An Extensible Compiler for Systems Programming Russ Cox Frans Kaashoek Eddie Kohler [email protected] Outline ..................................................................................................................... Why bother? What could it do? How could it work? Ground rules: ߝ interrupt with questions ߝ work in progress ߝ show and tell, not a job talk Man vs. Machine ߝ Linguistic Tensions ................................................... The most important readers of a program are people. -
[MS-SMB]: Server Message Block (SMB) Protocol
[MS-SMB]: Server Message Block (SMB) Protocol Intellectual Property Rights Notice for Open Specifications Documentation . Technical Documentation. Microsoft publishes Open Specifications documentation for protocols, file formats, languages, standards as well as overviews of the interaction among each of these technologies. Copyrights. This documentation is covered by Microsoft copyrights. Regardless of any other terms that are contained in the terms of use for the Microsoft website that hosts this documentation, you may make copies of it in order to develop implementations of the technologies described in the Open Specifications and may distribute portions of it in your implementations using these technologies or your documentation as necessary to properly document the implementation. You may also distribute in your implementation, with or without modification, any schema, IDL’s, or code samples that are included in the documentation. This permission also applies to any documents that are referenced in the Open Specifications. No Trade Secrets. Microsoft does not claim any trade secret rights in this documentation. Patents. Microsoft has patents that may cover your implementations of the technologies described in the Open Specifications. Neither this notice nor Microsoft's delivery of the documentation grants any licenses under those or any other Microsoft patents. However, a given Open Specification may be covered by Microsoft Open Specification Promise or the Community Promise. If you would prefer a written license, or if the technologies described in the Open Specifications are not covered by the Open Specifications Promise or Community Promise, as applicable, patent licenses are available by contacting [email protected]. Trademarks. The names of companies and products contained in this documentation may be covered by trademarks or similar intellectual property rights. -
Of File Systems and Storage Models
Chapter 4 Of File Systems and Storage Models Disks are always full. It is futile to try to get more disk space. Data expands to fill any void. –Parkinson’sLawasappliedto disks 4.1 Introduction This chapter deals primarily with how we store data. Virtually all computer systems require some way to store data permanently; even so-called “diskless” systems do require access to certain files in order to boot, run and be useful. Albeit stored remotely (or in memory), these bits reside on some sort of storage system. Most frequently, data is stored on local hard disks, but over the last few years more and more of our files have moved “into the cloud”, where di↵erent providers o↵er easy access to large amounts of storage over the network. We have more and more computers depending on access to remote systems, shifting our traditional view of what constitutes a storage device. 74 CHAPTER 4. OF FILE SYSTEMS AND STORAGE MODELS 75 As system administrators, we are responsible for all kinds of devices: we build systems running entirely without local storage just as we maintain the massive enterprise storage arrays that enable decentralized data replication and archival. We manage large numbers of computers with their own hard drives, using a variety of technologies to maximize throughput before the data even gets onto a network. In order to be able to optimize our systems on this level, it is important for us to understand the principal concepts of how data is stored, the di↵erent storage models and disk interfaces.Itisimportanttobeawareofcertain physical properties of our storage media, and the impact they, as well as certain historic limitations, have on how we utilize disks. -
Secure Compute Customization
ORNL/TM-2015/210 Review of Enabling Technologies to Facilitate Secure Compute Customization Approved for public release; distribution is unlimited. Ferrol Aderholdt Blake Caldwell Susan Hicks Scott Koch Thomas Naughton Daniel Pelfrey James Pogge Stephen L. Scott Galen Shipman Lawrence Sorrillo December 2014 DOCUMENT AVAILABILITY Reports produced after January 1, 1996, are generally available free via US Department of Energy (DOE) SciTech Connect. Website: http://www.osti.gov/scitech/ Reports produced before January 1, 1996, may be purchased by members of the public from the following source: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-605-6000 (1-800-553-6847) TDD: 703-487-4639 Fax: 703-605-6900 E-mail: [email protected] Website: http://www.ntis.gov/help/ordermethods.aspx Reports are available to DOE employees, DOE contractors, Energy Technology Data Exchange representatives, and International Nuclear Information System representatives from the following source: Office of Scientific and Technical Information PO Box 62 Oak Ridge, TN 37831 Telephone: 865-576-8401 Fax: 865-576-5728 E-mail: [email protected] Website: http://www.osti.gov/contact.html This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their em- ployees, makes any warranty, express 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 prod- uct, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorse- ment, recommendation, or favoring by the United States Govern- ment or any agency thereof.