How to get rid of slow CentOS mirrors on update

Get rid of slow CentOS mirrors on update.

Edit /etc/yum/pluginconf.d/fastestmirror.conf configuration file and exclude slow mirrors in the main section.

[main]
enabled=1
verbose=0
socket_timeout=3
hostfilepath=/var/cache/yum/timedhosts.txt
maxhostfileage=10
maxthreads=15

# Exclude slow/overloaded mirrors
exclude=mirror.slow.com, ftp.slow.mirror.com