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1.) Check the CentOS mirror sites page for a single site that would be best for a mirror site for youis in your area. Also consider reliability of the company or institution providing the mirror. Do some investigation on speed of the download speeds from the site.
2.) Test the mirror's cache settings for that site are set properly.
For a squid server : localhost
CentOS mirror site : http://mirrors.rit.edu/centos
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You should verify caching is working by your second build by looking for the string TCP_MEM_HIT in /var/log/squid/access.log.
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Advanced: Using your download proxy for testing installations
You can also use your
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download proxy server to install systems faster
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. To use the proxy, edit /etc/yum.conf and add the setting proxy=http://your-squid-server:3128 to the [main] section.
Next you'll want to edit as many of the repository files as you can to use a fixed location for downloading. To do this, comment out the lines starting with mirrorlist= and uncomment out lines #baseurl. To automate editing of repos files to use base urls instead or mirror lists, this command should work.sed -i -e 's/^mirrorlist/#mirrorlist/g' -e 's/^#baseurl/baseurl/g' /etc/yum.repos.d/*.repo
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