This might sound little crazy, but I want to disable yum plugin called the fast mirror. It always selects mirror hosted in my country which is very slow. As a result of all my yum command download file at 4-8Kb/s only. I am also behind a proxy server. How do I disable the fastest mirror plugin on CentOS Linux 6 or 7 server?

The fastest mirror plugin is intended for use in repository configurations where you have more than one mirror in a repo configuration. It makes yum to download packages from fastest and nearest mirror. If you are using the default CentOS configuration, and if you are not behind a proxy server, the fastest mirror is very much recommended option for everyone.

Disable yum command fastestmirror plugin on CentOS/Fedora

You need to edit the file named /etc/yum/pluginconf.d/fastestmirror.conf , run:
$ sudo vi /etc/yum/pluginconf.d/fastestmirror.conf
Find line that read as follows:
enabled=1
And set it as follows (set enabled to 0):
enabled=0
Save and close the file. Now run the following yum command:
$ sudo yum clean all
Sample outputs:

Cleaning repos: base epel extras updates
Cleaning up everything

Run yum update again:
$ sudo yum update
## try installing something ##
$ sudo yum install pkg
$ sudo yum install htop