DRBD Investigation

Today we learn about DRBD and how to use them (to start with)

The best resource to learn about it is from their main website http://www.drbd.org/

DRBD (Distributed Replicated Block Device) is a scheme for distributed replicated storage for the GNU/Linux platform. It is implemented as several userspace management applications and some shell scripts and is normally used on high availability (HA) clusters.

DRBD® refers to block devices designed as a building block to form high availability (HA) clusters. This is done by mirroring a whole block device via an assigned network. DRBD can be understood as network based raid-1.

A DRBD is essentially workload agnostic. A DRBD can be used as the basis of:

• A conventional file system,
• a shared disk file system such as GFS2 or OCFS2,
• another logical block device (as used in LVM, for example),
• any application requiring direct access to a block device

in our exercise we setup and install the following:

•  apache2
•  php5
•  mysql
•  php5-mysql

We open a terminal and type in the following commands toinstall them

apt-get install apache2

apt-get install php5

apt-get install mysql-server mysql-client mysql-common

apt-get install php5-mysql

To install DRBD we open a terminal and type the command:

sudo apt-get install drbd8-utils 

Then we configured DRBD by editing drbd.conf in the etc folder. This file should be the same on the servers.

In order to setup the DRBD then you must have installed Gparted to create a new partition. Usually Gparted is already installed on most linux based distros, if not then we open a terminal and use the command 

sudo apt-get install gparted

References:
http://www.drbd.org/
http://www.drbd.org/users-guide/ch-ocfs2.html