iotop is a utility for Linux that operates in a similar manner to the top utility, but it displays the I/O activity of each process.
Installation
First, you must enable the EPEL software repository:
For servers running RHEL 5:
rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm
For servers running RHEL 6:
rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-7.noarch.rpm
To install iotop:
yum -y install iotop
Usage
To display only the processes currently performing I/O:
iotop -o
To display the manual:
man iotop