UNIX

A redundant array of inexpensive disks (RAID) allows high levels of storage reliability. RAID is not a backup solution. It is used to improve disk I/O (performance) and reliability of your server or workstation. A RAID can be deployed using both software and hardware. But the real question is whether you should use a hardware RAID solution or a software RAID solution.

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Firefox version 3.5 has been released and available for download. Firefox 3.5 is the fastest web browser. It is twice as fast as Firefox 3. As a result javascript and multimedia enabled web apps loads faster. Firefox is the first browser to support open video and audio formats, allowing practically limitless new ways for sites to display rich content. This is based upon the open formats (HTML 5) which allow displaying media without a plug-in and/or proprietary software.

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Need to monitor Linux server performance? Try these built-in commands and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem. The commands discussed below are some of the most basic commands when it comes to system analysis and debugging server issues such as:

  1. Finding out bottlenecks.
  2. Disk (storage) bottlenecks.
  3. CPU and memory bottlenecks.
  4. Network bottlenecks.

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Anyone who has never made a mistake has never tried anything new. — Albert Einstein.

Here are a few mistakes that I made while working at UNIX prompt. Some mistakes caused me a good amount of downtime. Most of these mistakes are from my early days as a UNIX admin.

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If you do not control or throttle end users, your server may run out of resources. Spammers, abuser and badly written bots can eat up all your bandwidth. A webserver must keep an eye on connections and limit connections per second. This is serving 101. The default is no limit. Lighttpd can limit the throughput for each single connection (per IP) or for all connections. You also need to a use firewall to limit connections per second. In this article I will cover firewall and lighttpd web server settings to throttle end users. The firewall settings can be applied to other web servers such as Apache / Nginx and IIS server behind PF / netfilter based firewall.

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Apache Security Update – a flaw In Apache can be used to carry out DoS. Slowloris is a new Apache DoS tool which can use slow Internet links to bring down Apache servers, rather than flooding networks. Most D/DoS tool requires faster net connections but this tool works with minimal bandwidth. This tool can lead to a DoS attack on Apache 1.x, 2.x, dhttpd, GoAhead WebServer, and Squid, while MS IIS6.0, IIS7.0, and lighttpd are confirmed not vulnerable to this attack.

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UNIX turns 40 – in 1969 group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna developed UNIX. Today Unix offered in many flavors and developed over time by AT&T as well as various commercial vendors (such as IBM, HP, Sun, Apple etc) and non-profit organizations. CW article concluded that after four decades, the future of the operating system is clouded, but its legacy will endure in form of Linux and Microsoft NT operating system.

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