The BIOS Initialization Sequence

A basic understanding of the BIOS is a fundamental skill for all serious computer users. While many modern computers allow you to boot directly from the media of your choice, such as an RHEL 5 installation CD or a rescue USB key, that may not be possible during your troubleshooting. Therefore, you need to know how to modify the BIOS menu to boot from
the media of your choice.

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RAID Levels

RAID is an acronym first defined by David A. Patterson, Garth A. Gibson, and Randy Katz at the University of California, Berkeley in 1987 to describe a redundant array of inexpensive disks,[1] a technology that allowed computer users to achieve high levels of storage reliability from low-cost and less reliable PC-class disk-drive components, via the technique of arranging the devices into arrays for redundancy. Marketers representing industry RAID manufacturers later reinvented the term to describe a redundant array of independent disks as a means of dissociating a “low cost” expectation from RAID technology. In this article we will give you an idea about the different RAID levels. Feel free to comment the article on the bottom of it. Be aware that you need to register in order to leave your comment.

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KVM Red Hat Enterprise Linux

Red Hat announced a few months ago the release of Red Hat Enterprise Linux 5.4, a new major point update of the company’s popular commercial Linux distribution. This version introduces official support for KVM and marks an important milestone in Red Hat’s gradual transition away from Xen. KVM, the Kernel-based Virtual Machine, is an open source framework that brings native full virtualization to the Linux kernel. It is primarily designed for the x86 architecture (though others are supported) and takes advantage of processor virtualization extensions. It has been part of the mainline Linux kernel since 2.6.20 and has become the favored virtualization solution of the upstream kernel community.

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Configure DHCP

A DHCP server automates the network configuration process for clients. In detail, DHCP allows a Linux computer to serve dynamic IP addresses. It supports the configuration of a range of IP addresses and allows you to reserve a specific IP address, based on the hardware address associated with a client’s network card. It can assign more information such as the gateway and DNS IP address to every system that requests an IP address.

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PXE Booting

Most modern systems include some sort of network boot card and a BIOS that can take advantage of that capability. As a wide variety of options are available from the boot menu, they are not all described here.

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Upstart, RCs Scripts, and Services

If you haven’t installed a new version of Linux lately, you might be in for a shock. There is no /etc/inittab configuration file in Ubuntu releases. Upstart, the replacement for the System V init program, is designed to meet the demands of the latest plug-and-play hotplug environments. During the boot process, Upstart is especially helpful with filesystems mounted on portable and network devices.

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Synchronizing Servers with RYSNC and SSH on a cluster

This article describes one method of automating the copying of data and configuration files from one server to another in thoery. If you have enough knowledge on Linux systems it will be a matter of a few hours to deploy this scenario. In its simplest form, synchronizing the data on two (or more) servers is just a matter of copying files from one server to another. One server acts as a primary repository for data, and changes to the data can only be made on this server (in a high-availability configuration, only one server owns a resource at any given point in time). A regularly scheduled copy utility then sends the data after it has been changed on the primary server to the backup server so it is ready to take ownership of the resource if the primary server crashes. In a cluster configuration all nodes need to access and modify shared data (all cluster nodes offer the same services), so you will probably not use this method of data synchronization on the nodes inside the cluster. You can, however, use the method of data synchronization described in this article on highly available server pairs to copy data and configuration files that change infrequently.

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Cluster installation video

Directory Server 8.1 is comprised of several components, which work in tandem:

• The Directory Server is the core LDAP server daemon. It is compliant with LDAP v3 standards. This component includes command-line server  management and administration programs and scripts for common operations like export and backing up databases.

• The Directory Server Console is the user interface that simplifies managing users, groups, and other LDAP data for your enterprise. The Console is used for all aspects of server management, including making backups; configuring security, replication, and databases; adding entries; and monitoring
servers and viewing statistics.

• The Administration Server is the management agent which administers Directory Servers. It communicates with the Directory Server Console and performs operations on the Directory Server instances. It also provides a simple HTML interface and on-line help pages. There must be one Administration Server running on each machine which has a Directory Server instance running on it.

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Certified Engineer

In this article we will talk about RHCE prerequisites. For the RHCE and RHCT exams, the skills outlined in this article are generally minimum requirements. For example, while you may prefer to use an editor other than vi, you may not have access to the GUI, and therefore need to know how to use a console-based text editor on at least the Troubleshooting and System Maintenance section of the exam. While you’re not required to know how to pipe the output of dmesg to the less command, this is a useful tool that can help you identify problems.Critical to a Linux administrator is knowledge of one or more text editors to manage the many configuration files on a Linux system. The Linux filesystem hierarchy organizes hardware, drivers, directories, and, of course, files.

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