Tips

Get ready for a minute with 61 seconds. Scientists are delaying the start of 2009 by the first ‘leap second’ a timing tweak meant to make up for changes in the Earth’s rotation.

The aged Earth is slowing down in its daily rotation, at least in the current epoch. So a leap second is added (a one-second adjustment added) to our time. This year will be exactly one second longer.

Precise time measurements are needed for high-speed communications systems among other modern technologies such as clusters, GPS, networks. You need to make sure that you are running updated version of ntpd that support leap second for UNIX and Windows computers.

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Now, mod_fastcgi is configured and running. FastCGI supports connection via UNIX sockets or TCP/IP networking. This is useful to spread load among various backends. For example, php will be severed from 192.168.1.10 and python / ruby on rails will be severed from 192.168.1.11. This is only possible with mod_fastcgi.

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FastCGI is a protocol for interfacing interactive programs with a web server. FastCGI’s main aim is to reduce the overhead associated with interfacing the web server and CGI programs, allowing a server to handle more web page requests at once.

Also, PHP is not recommended with multithreaded Apache2 (worker MPM) because of performance and some 3rd party PHP extensions are not not guaranteed thread-safe.

nginx and lighttpd has inbuilt support for FastCGI. For Apache web server you need to use either mod_fastcgi or mod_fcgid.

mod_fastcgi allows server and application processes to be restarted independently — an important consideration for busy web sites. It also facilitates per-application security policies — important for ISPs and web hosting companies.

In this quick tutorial, you will learn about Apache 2 + mod_fastcgi + PHP installation and configuration under Red Hat Enterprise Linux / CentOS Linux version 5.x+.

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VirtualBox is a virtual emulator like VMWare workstation. It has many of the features VMWare has, as well as some of its own.

I really like new Opensource VirtualBox from Sun. It is light on resources. Here is a quick tip – you can convert a VMware virtual machine (image) to a VirtualBox machine (image) using qemu-img utility, without reinstalling the GUEST operating system

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This is 3rd and the final installment for Apache Chroot Jail for CentOS / RHEL series. Once Apache is configured with mod_chroot, you may need to test and debug problems. This article will provide a few troubleshooting tips.

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Wordpress version 2.7 has been released and can be upgraded easily using UNIX / Linux shell prompt. A few assumptions:

  1. Wordpress database name: wptheosblog
  2. Wordpress directory name: /var/www/html/theos.in
  3. Wordpress domain name: theos.in
  4. Operating system: Linux
WARNING! If you are not comfortable with UNIX shell prompt (IF YOU ARE new to a UNIX/Linux os), please follow traditional way of upgrading wordpress and DO NOT use the three Steps described here.

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I’ve already written about creating a partition size larger than 2TB under Linux using GNU parted command with GPT. In this tutorial, I will provide instructions for booting to a flat 2TB or larger RAID array under Linux using the GRUB boot loader.

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