安装好ubuntu后发现下载安装软件速度很慢，我的下载速度理论上有几M每秒的啊，原来是软件源问题。于是将默认的软件源更改为中国搜狐的软件源，测试速度
Download: 33.07 Mbit/s
Testing upload speed...................
Upload: 17.12 Mbit/s
发现很不错，达到了我的带宽。
更新软件源方法如下：
1.备份自带软件源(万一需要恢复的时候用，不能保证一次成功嘛）
sudo cp /etc/apt/source.list /etc/apt/source.list.backup
2. 编辑软件源更改为中国搜狐的源：（删除自带的源后复制下面搜狐的源到source.list保存即可）
sudo vim /etc/apt/source.list
##搜狐的软件源
deb http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
3.更新设置
sudo apt-get update
这样可以测试网速了，换了之后速度很快了。可以安装我的lamp了。