December 2008

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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I’ve already written about setting the MTU (Maximum Transmission Unit) under Linux including Jumbo frames (FreeBSD specific MTU information is here).

With this quick tip you can increase MTU size to get a better networking performance.

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Virtualization is the latest buzz word. You may wonder computers are getting cheaper every day, why should I care and why should I use virtualization? Virtualization is a broad term that refers to the abstraction of computer resources such as:

  1. Platform Virtualization
  2. Resource Virtualization
  3. Storage Virtualization
  4. Network Virtualization
  5. Desktop Virtualization

This article describes why you need virtualization and list commonly used FOSS and proprietary Linux virtualization software.

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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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Linux kernel version 2.6.28 has been released and available for download. The new version includes following stable and new features:

a] ext4 file system – The ext4 filesystem can support volumes with sizes up to 1 exbibyte and files with sizes up to 16 TiB. ext4 removes ext3 64-bit storage limits and adds other performance improvements.

b] Graphics Execution Manager (GEM) – It is a a modern memory manager specialized for use in device drivers for graphics chipsets. It manages graphics memory, controls the execution context and manages the Non-Uniform Memory Access (NUMA) environment on modern graphics chipsets. The “xf86-video-intel” device driver will feature GEM integration.

c] Other features – Stable USB drivers, KVM, bug fixes and other stuff.

=> Download Linux kernel 2.6.28 here. You may also find our kernel compile tutorial useful.

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Canonical the makers of Ubuntu about to introduce a new desktop notification system proposal. New changes should improve the usability of the Linux desktop including desktop notification system for both GNOME and KDE. From the Mark Shuttleworth blog:

The key proposals we are making are that:

* There should be no actions on notifications.

* Notifications should not be displayed synchronously, but may be queued. Our implementation of the notification display daemon will display only one notification at a time, others may do it differently.

That’s pretty much it. There are some subtleties and variations, but these are the key changes we are proposing, and which we will explore in a netbook device with a partner, as well as in the general Ubuntu 9.04 release, schedule gods being willing.

I think new changes looks more like Growl system used in Mac OS X. You can read more about proposal including mockup video that shows new notification system here.

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