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Linux Setting the Clock on Linux
Post date: April 12, 2005, 13:04 Category: System Views: 46
Tutorial quote: There are 3 protocols dealing with time: NTP (port 123), Time (port 37), and Daytime (port 13). If you're connecting to the Internet periodically, then synchronizing your clock when you dial up or from crontab is good enough. This applies also to most Linux machines at home or at work, even if they are connected all the time. Here is a short tutorial on how to set your clock using these 3 protocols.
Linux Building a Linux Cluster, Part 3: How To Get Started
Post date: April 25, 2005, 10:04 Category: Network Views: 74
Tutorial quote: In the previous two articles in this series, we examined some of the whys and whats of building Linux clusters. This article concludes our series by concentrating on the hows of cluster building. We've seen that a clustered approach to certain computing solutions can save lots of money in hardware and support costs. Now our job is to produce a method of building clusters that's repeatable and predictable—we don't want to give back our hard-won savings in project cost overruns.
Linux Linux Web Filtering in 7 steps
Post date: April 12, 2005, 14:04 Category: Network Views: 423
Tutorial quote: How to install a transparent Squid proxy server with real-time HTTP virus scanning on Mandrake 10.0 using DansGuardian and ClamAV?

People quickly and easily access volumes of research on the Internet and correspond with a mouse click. For more and more companies, content filtering is part of the large battle to combat all kinds of online threats, including hackers, worms and viruses. Linux content filtering allows administrators to configure and manage Internet access across the entire network and to block unwanted Web content like pornography, shopping Web sites, games and gambling.

This guide contains all the necessary information for installing and understanding the architectural layout of the implementation. It was written with the assumption that you understand how to install programs and have a basic understanding of Linux Mandrake. This includes installing Linux Mandrake and RPM packages, editing files, making directories, compiling software and understanding general UNIX commands. This guide doesn’t explain how to use or configure Squid, DansGuardian and ClamAV but information on where to obtain this information can be found in the “Additional information” section.
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.
SuSe Working with SUSE Linux Enterprise Server 9
Post date: June 22, 2005, 05:06 Category: System Views: 130
Tutorial quote: Working with SUSE Linux Enterprise Server (SLES) requires an understanding of the login process, including local account files, system accounts, and managing identities.

Using a console shell or the graphical environment are two possible methods of working on a SLES machine.

Finding your way around a SLES installation requires an in-depth knowledge of the filesystem layout. Essential filesystem components are documented and explained in this chapter. Basic filesystem permissions are also described.
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.