Memcached and PECL memcache on CentOS

At Tag1 Consulting we do a lot of work on increasing web site performance, especially around Drupal sites. One of the common tools we use is memcached combined with the Drupal Memcache module. In Drupal, there are a number of different caches which are stored in the (typically MySQL) database by default. This is good for performance as it cuts down on potentially large/slow SQL queries and PHP execution needed to display content on a site.

How to reset Webmin root password?

At times we often forget the webmin password for a given user, say root, or after repeated failed login attempts webmin locks the account and one cannot login anymore. In this case you need to wait for couple, three minutes and you will be able to try to login again. However, if you've forgotten your password and need to change it, then login to the server via ssh and run the following command:

For RHEL/CentOS:

/usr/libexec/webmin/ /etc/webmin root NEWPASSWORD

For Debian/Ubuntu

/usr/share/webmin/ /etc/webmin root NEWPASSWORD

How to install the latest version of GIT on Centos 6.x?

To install the current stable version of git just launch simple command:

yum install git

Probably you could compile even newer version of git from the source. However, the purpose of this tutorial is to show how to install the latest version of git available in the repositories.

Install RPMforge repository following instructions on


How to install php-mcrypt on CentOs 6.3

You need EPEL repo to install php-mcrypt:

yum -y install
yum -y install php-mcrypt

Here is the code for installing EPEL repository on CentOS 6.4:

rpm -Uvh


How to install APC on CentOS 6.2

Various instructions in Internet on the subject did not give any joy, so compiling my own sequence, which did the trick:

yum install php-pear php-devel httpd-devel gcc pcre-devel apc
nano /etc/php.d/apc.ini

Put the following in apc.ini:

; Enable apc extension module

Then copy apc.php to public_html directory of your website:

How do you increase a KVM guest's disk space?

How do you go about increasing KVM virtual machine guest's disk space from the command line if you initially set insufficient amount of disk space?

  1. Shutdown the VM
  2. Move the current image

    mv mykvm.img mykvm.img.bak
  3. Create a new image

    qemu-img create -f raw addon.raw 30G
  4. concatenate the 2 images

    cat mykvm.img.bak addon.raw >> mykvm.img
  5. start the VM (using the newly created mykvm.img)
  6. run fdisk inside VM and delete & re-create LVM partition
    % fdisk /dev/vda

Partition X does not end on cylinder boundary

While reviewing the partion layout on one of my hard drives, I noticed a number of “Partition X does not end on cylinder boundary” messages in the fdisk output:

$ fdisk /dev/sda
Command (m for help): p

Disk /dev/sda: 80.0 GB, 80000000000 bytes
255 heads, 63 sectors/track, 9726 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xac42ac42

Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.


Virt-manager keymap problem on OS X

virt-manager keymaps on OS X
Published on Wed, 17 Nov 2010 20:12:26 +0000 in Uncategorized. 13 Comments


How to completely remove APF from Ubuntu

Running 'apt-get remove --purge apf-firewall' often times is not enough, especially if you tried to modify APF's files and paths. So to completely clean up your Ubuntu system form APF (Advanced Policy Firewall) your also need to run the following commands:

[email protected]:/etc/apt# rm -rf /var/lib/dpkg/info/apf*
[email protected]:/etc/apt# rm -rf /usr/src/apf*
[email protected]:/etc/apt# rm -rf /usr/share/man/man1/apf*
[email protected]:/etc/apt# rm -rf /usr/share/doc/apf*
[email protected]:/etc/apt# rm -rf /usr/local/sbin/apf
[email protected]:/etc/apt# rm -rf /usr/sbin/apf
[email protected]:/etc/apt# rm -rf /etc/rc0.d/K20apf*

How to install XHProf profiler on Ubuntu

XHProf profiler is developed by Facebook and open sourced in March 2009 under the Apache 2.0 license. XHProf is a function-level hierarchical profiler, with a PHP extension (written in C) to collect the raw data, and a few PHP scripts for the reporting/UI layer.

The easiest way to get it is via the PEAR installer (package home):

install php5-common
pear channel-update
pecl install xhprof

Once you have XHProf installed, you should enable it. Open your /etc/php5/conf.d/xhprof.ini and add




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