Linux拥有众多的发行版，每个发行版都有提供镜像，但是，有些镜像的下载速度参差不齐，偶尔会有更新失败的情况。

下面以修改 Debian 软件源为 未来云为例进行说明(镜像地址/香港节点镜像地址)：

1、备份原配置文件

# cp /etc/apt/sources.list /etc/apt/sources.list.backup 

2、修改软件源配置文件

debian 7.x (wheezy)

编辑/etc/apt/sources.list文件, 将内容修改为：

 deb http://mirrors.niaoyun.com/debian/ wheezy main non-free contrib
 deb http://mirrors.niaoyun.com/debian/ wheezy-proposed-updates main non-free contrib
 deb-src http://mirrors.niaoyun.com/debian/ wheezy main non-free contrib
 deb-src http://mirrors.niaoyun.com/debian/ wheezy-proposed-updates main non-free contrib    

debian 8.x (jessie)

编辑/etc/apt/sources.list文件, 将内容修改为：

deb http://mirrors.niaoyun.com/debian/ jessie main non-free contrib
deb http://mirrors.niaoyun.com/debian/ jessie-proposed-updates main non-free contrib
deb-src http://mirrors.niaoyun.com/debian/ jessie main non-free contrib
deb-src http://mirrors.niaoyun.com/debian/ jessie-proposed-updates main non-free contrib

如果是香港节点：

debian 7.x (wheezy)

编辑/etc/apt/sources.list文件, 将内容修改为：

deb http://hk.mirrors.niaoyun.com/debian/ wheezy main non-free contrib
deb http://hk.mirrors.niaoyun.com/debian/ wheezy-proposed-updates main non-free contrib
deb-src http://hk.mirrors.niaoyun.com/debian/ wheezy main non-free contrib
deb-src http://hk.mirrors.niaoyun.com/debian/ wheezy-proposed-updates main non-free contrib        

debian 8.x (jessie)

编辑/etc/apt/sources.list文件, 将内容修改为：

deb http://hk.mirrors.niaoyun.com/debian/ jessie main non-free contrib
deb http://hk.mirrors.niaoyun.com/debian/ jessie-proposed-updates main non-free contrib
deb-src http://hk.mirrors.niaoyun.com/debian/ jessie main non-free contrib
deb-src http://hk.mirrors.niaoyun.com/debian/ jessie-proposed-updates main non-free contrib

3、更新

# apt-get update