Linux

The best Linux file system, Ext2 or Ext4?

Google, which knows a thing or two about fast systems has decided,…

Google, which knows a thing or two about fast systems has decided, for their purposes anyway, that Ext4 is the best and close to the fastest file system of all.

Google’s Michael Rubin, a senior staff engineer, wrote, “Google is currently in the middle of upgrading from ext2 to a more up to date file system. We ended up choosing ext4.”

Rubin then explains, “The driving performance reason to upgrade is that while ext2 had been ‘good enough’ for a very long time the metadata arrangement on a stale file system was leading to what we call “read inflation”. This is where we end up doing many seeks to read one block of data. In general latency from poor block allocation was causing performance hiccups.”

Linux

Installing rar/unrar On CentOS 6

Open up ssh client and connect to the server as root user.…

Open up ssh client and connect to the server as root user.

For 32bit:
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.i386.rpm

For 64bit:
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm

Install DAG’s GPG key:
rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt

If you get an error message like the following the key has already been imported:
[error]error: http://apt.sw.be/RPM-GPG-KEY.dag.txt: key 1 import failed.[/error]

Linux

Installing rar/unrar On CentOS 5

Open up ssh client and connect to the server as root user.…

Open up ssh client and connect to the server as root user.

For 32bit:
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm

For 64bit:
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.x86_64.rpm

Install DAG’s GPG key:
rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt

Linux

Apache Log Files on Server

Q. How do I find out Apache http server log files location?…

Q. How do I find out Apache http server log files location? How do I change the location of Apache log file under Linux / UNIX operating system?

A. There are two type of apache httpd server log files:

Apache Error Log File

All apache errors / diagnostic information other errors found during serving requests are logged to this file. Location of error log is set using ErrorLog directive. If there is any problem, you should first take a look at this file using cat, grep or any other UNIX / Linux text utilities. This apache log file often contain details of what went wrong and how to fix it. Default error log file location:

  • RHEL / Red Hat / CentOS / Fedora Linux Apache error file location – /var/log/httpd/error_log
  • Debian / Ubuntu Linux Apache error log file location – /var/log/apache2/error.log
  • FreeBSD Apache error log file location – /var/log/httpd-error.log