Prerequisites – Setup Minimal CentOS 5 – be sure that both nodes can resolve correctly names (either through dns or /etc/hosts) – yum update – yum install heartbeat drbd kmod-drbd (available in the extras repository) Current situation : node1.yourdomain.org 172.29.156.20/24 , source disc /dev/sdb that will be replicated node2.yourdomain.org 172.29.156.21/24 , target disc /dev/sdb DRBD [...]
 MySQL supports several storage engines that act as handlers for different table types. MySQL storage engines include both those that handle transaction-safe tables and those that handle non-transaction-safe tables: MyISAM manages non-transactional tables. It provides high-speed storage and retrieval, as well as fulltext searching capabilities. MyISAM is supported in all MySQL configurations, and is the default storage engine [...]
Some hardware manufacturers offer fault tolerance with their network adapters and accompanying drivers. Fault tolerance technology lets you group network adapter ports for a connection to a single physical segment. If connectivity through one port does not work, another port is opened automatically. This operation is transparent to the operating system and other devices on [...]
The inittab file /etc/inittab also describes which processes are started at bootup and during normal operation. For example, Oracle uses it to start cluster services at bootup. Therefore, it is recommended to ensure that all entries in /etc/inittab are legitimate in your environment. I would at least remove the CTRL-ALT-DELETE trap entry to prevent accidental [...]
Usually a firewall is used to protect a server from other servers and networks. However, in some cases you may also want to protect a server within a network by using a TCP Wrapper. The Xinetd super server that comes with most Linux distributions includes a built-in TCP wrapper. It can be used to explicitly [...]
What is Asterisk Asterisk is the world’s leading open source telephony engine and tool kit. Offering flexibility unheard of in the world of proprietary communications, Asterisk empowers developers and integrators to create advanced communication solutions…for free. Asterisk® is released as open source under the GNU General Public License (GPL), and it is available for download [...]
A very old tip and trick on blocking yahoo chat messenger from connecting to internet, as per request. Considering an approved management policies, there are several ways to block yahoo chat messenger from connecting to internet coming from inside your network, depending on what equipment and boxes you have on ground. If you happen to [...]
Most popular distro kernels ship with the bonding driver already available as a module and the ifenslave user level control program installed and ready for use. If your distro does not, or you have need to compile bonding from source (e.g., configuring and installing a mainline kernel from kernel.org), you’ll need to perform the following [...]
Important points about RSG • An RSG can be used only to recover mailbox data. To recover public folder data, you must use a recovery forest and recovery server. • RSGs cannot be used to recover mailboxes that have been deleted. • In order to use an RSG, you must have a backup of the [...]
To NTFS or not to NTFS—that is the question. But unlike the deeper questions of life, this one isn’t really all that hard to answer. For most users running Windows XP, NTFS is the obvious choice. It’s more powerful and offers security advantages not found in the other file systems. But let’s go over the [...]
LVS has a built-in simple IP based persistence mechanism that can be used to keep users on the same real servers for a configurable amount of time. If your web application requires that each user request to be processed by the same real server then you will probably want to enable this mechanism and ensure [...]
Domain name Servers (DNS) are an important but invisible part of the internet, and form one of the largest databases on it. Each machine on an internet is assigned a unique address, called an IP address, which is 32 bit number and is expressed as 4 octets. The method user to represent these IP addresses [...]
System state backups are critical on each server because these are the tools that protect the operating system itself. There are nine potential elements to a system state backup. Some are always backed up and others depend on the type of server you are backing up. They are identified as follows: • The system registry [...]
Log in as root to the Zimbra server and cd to the directory where the Zimbra Collaboration Suite archive tar file is saved (cd /var/). Type the following commands: tar xzvf [zcsfullfilename.tgz], to unpack the file cd [zcsfullfilename] to change to the correct directory. ./install.sh, to begin the installation The install.sh script reviews the installation [...]