中科大的源质量速度都不错，推荐使用。
这里列出CentOS 7的Base和epel的源。
进入/etc/yum.repos.d/中，将原本的几个repo文件备份，之后新建三个repo文件
内容如下：
1.CentOS-Base.repo: # CentOS-Base.repo # # The mirror system uses the connecting IP address of the client and the # update status of each mirror to pick mirrors that are updated to and # geographically close to the client. You should use this for CentOS updates # unless you are manually picking other mirrors. # # If the mirrorlist= does not work for you, as a fall back you can try the # remarked out baseurl= line instead. # # [base] name=CentOS-$releasever - Base #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os baseurl=http://mirrors.ustc.edu.cn/centos/$releasever/os/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 #released updates [updates] name=CentOS-$releasever - Updates # mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates baseurl=http://mirrors.ustc.edu.cn/centos/$releasever/updates/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 #additional packages that may be useful [extras] name=CentOS-$releasever - Extras # mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras baseurl=http://mirrors.ustc.edu.cn/centos/$releasever/extras/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 #additional packages that extend functionality of existing packages [centosplus] name=CentOS-$releasever - Plus # mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus baseurl=http://mirrors.ustc.edu.cn/centos/$releasever/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 2.epel.repo: [epel] name=Extra Packages for Enterprise Linux 7 - $basearch baseurl=http://mirrors.ustc.edu.cn/epel/7/$basearch #mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=$basearch failovermethod=priority enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 [epel-debuginfo] name=Extra Packages for Enterprise Linux 7 - $basearch - Debug baseurl=http://mirrors.ustc.edu.cn/epel/7/$basearch/debug #mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-7&arch=$basearch failovermethod=priority enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 gpgcheck=1 [epel-source] name=Extra Packages for Enterprise Linux 7 - $basearch - Source baseurl=http://mirrors.ustc.edu.cn/epel/7/SRPMS #mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-7&arch=$basearch failovermethod=priority enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 gpgcheck=1 3.epel-testing.repo: [epel-testing] name=Extra Packages for Enterprise Linux 7 - Testing - $basearch baseurl=http://mirrors.ustc.edu.cn/epel/testing/7/$basearch #mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-epel7&arch=$basearch failovermethod=priority enabled=0 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 [epel-testing-debuginfo] name=Extra Packages for Enterprise Linux 7 - Testing - $basearch - Debug baseurl=http://mirrors.ustc.edu.cn/epel/testing/7/$basearch/debug #mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-debug-epel7&arch=$basearch failovermethod=priority enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 gpgcheck=1 [epel-testing-source] name=Extra Packages for Enterprise Linux 7 - Testing - $basearch - Source baseurl=http://mirrors.ustc.edu.cn/epel/testing/7/SRPMS #mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-source-epel7&arch=$basearch failovermethod=priority enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 gpgcheck=1 之后执行yum makecache