mount local yum source

system: CentOS 6.6

two steps:

1. 

mkdir /root/repo

cp /etc/yum.repos.d/* /root/repo/

rm -rf /etc/yum.repos.d/*

cp /root/repos/CentOS-Media.repo /etc/yum.repos.d/

vim Centos-Media.repo

change it to

baseurl=file:///media/CentOS/

gpgcheck=0

enabled=1

2. 

mkdir /media/CentOS

mount /dev/sda1 /media/CentOS

yum clean all

yum list