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Unix+clones Xen Disk I/O benchmarking: NetBSD dom0 vs Linux dom0
Post date: April 21, 2005, 06:04 Category: Benchmarks Views: 107
Tutorial quote: Xen is a relatively new technology to enable several virtual machines (domU) to run on one computer. The purpose of this article is to determine what operating system (NetBSD or Linux) should be selected as domain 0 (dom0) operating system to get the best performance when running several CPU and disk intensive virtual machines at the same time.
OpenSUSE Hacking OpenSUSE
Post date: December 3, 2005, 12:12 Category: System Views: 133
Tutorial quote: There's more to SUSE Linux than simply installing it and going to work. To get the most from the operating system, you'll probably want to do some post-install fine tuning. This article by Jem Matzan explains how to: add download sources to YaST; install the Mozilla Thunderbird email client; add support for Java, Flash, Acrobat, Windows Media, MP3s, and RealMedia; play DVDs -- and more. It serves as a useful supplement to Steven J. Rosen's excellent how-to, "Installing SUSE Linux 10 on a Laptop," recently published here on DesktopLinux.com. Enjoy . . . !
Unix+clones Encrypted NFS with OpenSSH
Post date: May 21, 2005, 15:05 Category: Network Views: 44
Tutorial quote: NFS is a widely deployed, mature, and understood protocol that allows computers to share files over a network. The main problems with NFS are that it relies on the inherently insecure UDP protocol, transactions are not encrypted, hosts and users cannot be easily authenticated, and its difficulty in firewalling. This article provides a solution to most of these problems for Linux clients and servers. These principles may also be applied to any UNIX server with ssh installed. This article assumes basic knowledge of NFS and firewalling for Linux.
Linux Grub From the Ground Up
Post date: April 12, 2005, 13:04 Category: Software Views: 39
Tutorial quote: Grub is a world-class boot loader with insufficient documentation. In many ways it blows the doors of LILO. For instance, it's MUCH easier to use Knoppix to rebuild a grub boot loader than to rebuild a LILO boot loader. However, until you're comfortable with grub, it might seem just the opposite. All too often grub dumps you at a grub> prompt with no hint of what you should do. You might have heard that a successful reboot is just three commands away, but which commands? The state of grub's documentation is such that you can't figure it out unless you already know grub.

That catch 22 is the very purpose of this document. This document will to give you enough grub expertise that you can create a grub boot floppy on a working machine with grub installed (not necessarily as the bootloader, just installed), and use that floppy to bust back into a Linux machine with a blown bootloader, and then use that floppy to actually install grub as the bootloader.

This document does not discuss using grub to boot or dual boot Windows, mach, BSD, or other non-Linux operating systems. I might write on that subject later. But in the meantime, once you're familiar with the principles and practices of grub, given some study of existing documentation you'll probably be able to use grub to boot non-Linux operating systems.
Linux Creating Really Teensy ELF Executables for Linux
Post date: April 12, 2005, 14:04 Category: Miscellaneous Views: 34
Tutorial quote: If you're a programmer who's become fed up with software bloat, then may you find herein the perfect antidote.

This document explores methods for squeezing excess bytes out of simple programs. (Of course, the more practical purpose of this document is to describe a few of the inner workings of the ELF file format and the Linux operating system. But hopefully you can also learn something about how to make really teensy ELF executables in the process.)

Please note that the information and examples given here are, for the most part, specific to ELF executables on a Linux platform running under an Intel-386 architecture. I imagine that a good bit of the information is applicable to other ELF-based Unices, but my experiences with such are too limited for me to say with certainty.

The assembly code that appears in this document is written for use with Nasm. (Besides being more appropriate for our needs, Nasm's syntax beats the hell out of AT&T syntax for anyone who learned x86 assembly language before learning to use Gas.) Nasm is freely available and extremely portable; see http://nasm.sourceforge.net/.

Please also note that if you aren't a little bit familiar with assembly code, you may find parts of this document sort of hard to follow.
Debian dmcrypt
Post date: January 25, 2006, 17:01 Category: Security Views: 85
Tutorial quote: Device-mapper is a new infrastructure in the Linux 2.6 kernel that provides a generic way to create virtual layers of block devices that can do different things on top of real block devices like striping, concatenation, mirroring, snapshotting, etc... The device-mapper is used by the LVM2 and EVMS 2.x tools. dm-crypt is such a device-mapper target that provides transparent encryption of block devices using the new Linux 2.6 cryptoapi. Writes to this device will be encrypted and reads decrypted. You can mount your filesystem on it as usual. But without the key you can't access your data. It does basically the same as cryptoloop only that it's a much cleaner code and better suits the need of a block device and has a more flexible configuration interface. The on-disk format is also compatible.
Debian Building A Virtual Server (VPS) With Debian 3.1 (Sarge) And OpenVZ
Post date: March 20, 2006, 15:03 Category: System Views: 36
Tutorial quote: In this HowTo I will describe the steps to be taken to prepare a server for OpenVZ virtual machines on Debian 3.1 (Sarge) 32Bit Linux. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernal patch is licensed under the GPL license, and the user-level tools are under the QPL license.
Linux Building a Linux virtual server
Post date: June 9, 2005, 10:06 Category: Software Views: 118
Tutorial quote: With the explosive growth of the Internet, the workload on servers providing Web, email, and media services has increased greatly. More and more sites are being challenged to keep up with the growing demands and are employing several techniques to avoid overloading their servers. Building a scalable server on a cluster of computers is one of the solutions that is being effectively put to use. With such a cluster, the increasing requests can be easily managed by simply adding one or more new servers to the existing cluster as required. In this article we will look at setting up one such scalable, network load-balancing server cluster using a virtual server via the Linux Virtual Server Project.
Unix+clones Easy Automated Snapshot-Style Backups with Linux and Rsync
Post date: January 31, 2006, 19:01 Category: Software Views: 27
Tutorial quote: This document describes a method for generating automatic rotating "snapshot"-style backups on a Unix-based system, with specific examples drawn from the author's GNU/Linux experience. Snapshot backups are a feature of some high-end industrial file servers; they create the illusion of multiple, full backups per day without the space or processing overhead. All of the snapshots are read-only, and are accessible directly by users as special system directories. It is often possible to store several hours, days, and even weeks' worth of snapshots with slightly more than 2x storage. This method, while not as space-efficient as some of the proprietary technologies (which, using special copy-on-write filesystems, can operate on slightly more than 1x storage), makes use of only standard file utilities and the common rsync program, which is installed by default on most Linux distributions. Properly configured, the method can also protect against hard disk failure, root compromises, or even back up a network of heterogeneous desktops automatically.
Linux The PartImage Handbook
Post date: May 21, 2005, 11:05 Category: Software Views: 43
Tutorial quote: - Partition Image is a Linux/UNIX partition imaging utility: it saves partitions formatted using the Ext2FS (the linux standard), ReiserFS (a new journaled and powerful file system), JFS IBM journaled file systems from AIX, NTFS (Windows NT File System), FAT16/32 (DOS & Windows file systems), or HPFS (OS/2 file system) file system formats to an image file. Only used blocks are copied. The image file can be compressed in the GZIP/BZIP2 formats to save disk space, and split into multiple files to be copied on removable media (ZIP for example), or burned on a CD-R ...

- This allows the user to save a full Linux/Windows system, with a single operation. When problems occur (viruses, crash, error, ...), you just have to restore, and after several minutes, all your system is restored (boot, files, ...), and fully working.

- This is very useful when installing the same software on many machines: just install one of them, create an image, and then restore the image on all other machines. After the first one, each subsequent installation can be made automaticaly, and only requires a few minutes.