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Showing posts from April, 2007

Virtualization : Basic Concepts

Virtualization is the creation of a virtual (rather than actual) version of something, such as an operating system, a server, a storage device or network resources. e.g. hard drive into different partitions, a partition is the logical division of a hard disk drive to create, in effect, two separate hard drives. Similarly, Operating system virtualization is the use of software to allow a piece of hardware to run multiple operating system images at the same time. There are three areas of IT where virtualization is making head roads a) Network virtualization b) Storage virtualization c) Server virtualization Today, virtualization is in the forefront - helping businesses with scalability, security and management of their global IT infrastructure. Virtualization can host multiple guest operating systems. Each guest operating system runs in its own domain, Virtualization schedules virtual CPUs within the virtual machines to make the best use of the available physical CPUs. Each

Change the default port for SSh user

Default port for SSH user is 22. But we can change the default port to some another port. eg. I want to run ssh service on port 99 instead of 22. Make the following change. open files #emacs /etc/ssh/ssh_config #emacs /etc/ssh/sshd_config search for port ie is default port = 22 make port = 99 or You can run on any port, But make sure other service not running on that port.

web Based administration solution for Linux : webmin

Webmin is an open source web Based administration solution for Linux. The purpose of webmin is to gather the administration of many different tasks and services under a common web interface. The software is perl based and module based which make it adaptable. Most common tasks have a module to administer. how To Install Webmin: # cd /usr/src # wget http://prdownloads.sourceforge.net/webadmin/webmin-1.340-1.noarch.rpm # rpm -ivh webmin-1.340-1.noarch.rpm steps to install virtualmin & configure it: login to webmin: ipaddress:100000 1) webmin -> webmin configuration -> webmin modulesInstall module -> from ftp or http url ->virtual min url is: http://download.webmin.com/download/virtualmin/virtual-server-3.201.gpl.wbm.gz 2) Enable https:yum install mod_sslin virtualmin config enable ssl for websites. Configuring virtualmin:Enabled the subverion and mysql moduledisabled webalizerPostgreSQL setup and configuration enabled? yes. 3) If this server is going to use PGsqlPostfix

Check your memory !

We all are always worry about memory weather it is main memory, secondary, or other swap These are few command which help u to debug your memory. Simple stat. #free #du -h #df -h Some complex stat. #cat /proc/meminfo #dmesg | grep -n kernel This command give you files have more than 100M usages. #find / -size +100M -fprintf /root/big.txt '%-10s %p\n'