Roderick Derks

The file system is one of the most important parts of an operating system. The file system stores and manages user data on disk drives, and ensures that what's read from storage is identical to what was originally written. In addition to storing user data in files, the file system also creates and manages information about files and about itself. Besides guaranteeing the integrity of all that data, file systems are also expected to be extremely reliable and have very good performance.

For the past several years, Ext2 has been the de facto file system for most Linux machines. It's robust, reliable, and suitable for most deployments. However, as Linux displaces Unix and other operating systems in more and more large server and computing environments, Ext2 is being pushed to its limits. In fact, many now common requirements — large hard-disk partitions, quick recovery from crashes, high-performance I/O, and the need to store thousands and thousands of files representing terabytes of data — exceed the abilities of Ext2.

Fortunately, a number of other Linux file systems take up where Ext2 leaves off. Indeed, Linux now offers four alternatives to Ext2: Ext3, ReiserFS, XFS, and JFS. In addition to meeting some or all of the requirements listed above, each of these alternative file systems also supports journaling, a feature certainly demanded by enterprises, but beneficial to anyone running Linux. A journaling file system can simplify restarts, reduce fragmentation, and accelerate I/O. Better yet, journaling file systems make fscks a thing of the past.

If you maintain a system of fair complexity or require high-availability, you should seriously consider a journaling file system. Let's find out how journaling file systems work, look at the four journaling file systems available for Linux, and walk through the steps of installing one of the newer systems, JFS. Switching to a journaling file system is easier than you might think, and once you switch — well, you'll be glad you did.

(This article taken from the www.linux-mag.com website, author Steve Best)

read more

In the Linux world, package management systems such as the RPM Package Manager (RPM) and Debian packages have become standard features with most distributions. Package management systems enable easy installs, de-installs, upgrades, and verification of both simple and complex software packages.

The basic tools for both RPM and Debian packages, though, work on individual package files. As Linux distributions have become larger and more complex and as the need for frequent and even automated updates has grown, the limitations of RPM and Debian packages have become apparent.

To fill this void, distribution maintainers have developed tools that either build on existing package systems or scrap them entirely in favor of new systems. Gentoo looked to FreeBSD for the inspiration for its Portage package management, which is network- and source code-based. Debian developers created the Advanced Package Tools (APT) to add network capabilities to Debian packages. In addition to an RPM port of APT, the RPM world has the Yellow Dog Updater, Modified, or Yum, which is similar to APT in basic features and design goals, although it differs in many details.

If you have an RPM-based system, investigating Yum (or APT, if you prefer) is worthwhile. Yum allows you to quickly and easily update the software on your system using network repositories or install entirely new packages.

This article is a copy from www.linux-mag.com, written by Roderick W. Smith. 🙂 Another Roderick..

read more

This is boring stuff, but needed to build and maintain your ldap directory. read more

Here I got this script for you that can help you to secure your server from attackers or bots.
Just add ip addresses you want to block to a file, on each line one, and run the script. Iptables will do the rest. read more

Using LDAP now… and no,  it is not a drug.  I started to set up LDAP on my home network to get a better understanding of this service. I'm getting there but it takes time.
Using: Fedora 6, openldap. And the Thunderbird email client to look up my email addresses.

read more

Needed:

• Computer (Virtual is an option)
• 2 NIC's
• ADSL modem
• linux and iptables

read more

Adding some hints here to secure your mailserver. The list will grow in time. 

$ vi /etc/mail/access

$ service sendmail reload 

Setup the config files for dhcp and Named. Clients (pc's, laptops) will get an ip address from a range you specified. You can also reserve specific ip address for static devices like serves or printers. The dhcp server daemon registers them to the Named server.

I used Fedore 6, dhcpd and Named running in chroot mode.

Sometimes you get stuck because of problems with rights on the file system or a configuration error in one of your config files. Don't let this bring you down. Stand up straight, keep you head up and hold on till you got what you wanted 😉 

read more