Archive for the 'linux' Category

Web server cluster with SUSE Linux Enterprise Server 10

Spreading a workload across multiple processors, coupled with various software recovery techniques, provides a highly available environment and enhances overall RAS (Reliability, Availability, and Serviceability) of the environment. Benefits include faster recovery from unplanned outages, as well as minimal effects of planned outages on the end user.To get the most out of this article, you should be familiar with Linux and basic networking, and you should have Apache servers already configured. Our examples are based on standard SUSE Linux Enterprise Server 10 (SLES10) installations, but savvy users of other distributions should be able to adapt the methods shown here.

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Make a copy of virtual machine with Vmware Server

It’s proven to be that during software development process, research activities and etc., using of virtulization is invaluable. In my practice I use Vmware Server, so the next article would be useful.

First of all, we need to find where all our virtual machines are in our system. After small search I’ve found vmware files in /var/lib/vmware/Virtual Machines. There are some set of directories each corresponds to some of your already created virtual machines. In my case I was interested in cloning virtual machine with name db1 to new machine db2 and then to db3.

Continue reading about virtual machines cloning with Vmware Server…

Vim text editor manual for newbies

Vim is a highly configurable text editor built to enable efficient text editing. It is an improved version of the vi editor distributed with most UNIX systems.Vim is often called a “programmer’s editor,” and so useful for programming that many consider it an entire IDE. It’s not just for programmers, though. Vim is perfect for all kinds of text editing, from composing email to editing configuration files.

Here is a link list of online manuals for newbies:

vimdoc: html + pdf
eandem: pdf
Hawaii College of Engineering: html +pdf

Find out where Unix/Linux executable binary is located

There are two commands that may help you to find where executable binary is located regardless it’s Unix or Linux system. They are whereis and type. First locates source/binary and manuals sections for specified files and second tells what exactly shell executes when you type a certain command.

The next picture shows examples of these commands work.

Find out where Unix/Linux executable binary is located

Desktop Linux distributions popularity 2007

Which Linux distros do we use on our home or office desktop system(s)?

2007-distributions-sm.jpg

More information is here.

Secure shell (ssh) session timeout

I’ve noticed that when I keep ssh sessions that I opened before untouched for some period of time (like 30 minutes) they become frozen and as a result I have to close ssh terminal and start a new connection. To prevent such situation I found several tips:

1) Start some utility updating the screen before leaving ssh session untouched. I usually use watch -n 1 ‘date’ that shows current date every second. Other simple way is to send icmp requests to some host, e.g. ping google.com.

2) Increase ssh session idle time by

echo “7200” > /proc/sys/net/ipv4/tcp_keepalive_time

I’ve checked these tips with Fedora Core, CentOS, Debian and Ubuntu but I’m completely sure that it applicable also for other Linux distributions. First tip (ping) can be used in Unix also.

 

Switching from Windows to Linux help resource

Here is a nice web site that may be useful for users who are going to switch to Linux from Windows.

applications.jpg


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