YUM安装软件包提示[Errno 256] No more mirrors to try的解决办法。YUM配置好后，使用yum命令进行安装时，出现了如下错误：

Downloading Packages:

ftp://192.168.220.46/RHEL6.2/x64/Server/libaio-devel-0.3.107-10.el6.x86_64.rpm: [Errno 14] PYCURL ERROR 19 - "Given file does not exist"
Trying other mirror.

Error Downloading Packages:
  libaio-devel-0.3.107-10.el6.x86_64: failure: libaio-devel-0.3.107-10.el6.x86_64.rpm from RHEL6.2-Server-X64: [Errno 256] No more mirrors to try.
 

原来是RHEL操作系统没有默认安装ftp工具，那就从光盘再安装一下ftp工具：

记得先加载系统ios文件，找到Packages目录，然后执行安装：

[root@instsvr1 Packages]# rpm -ivh ftp-0.17-51.1.el6.x86_64.rpm 
warning: ftp-0.17-51.1.el6.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID fd431d51: NOKEY
Preparing...                ########################################### [100%]
   1:ftp                    ########################################### [100%]