[root@chefserver dir]# gem install mysql2 Building native extensions. This could take a while... Successfully installed mysql2-0.3.11 1 gem installed Installing ri documentation for mysql2-0.3.11... Installing RDoc documentation for mysql2-0.3.11...

[root@chefserver dir]# irb irb(main):001:0> require 'mysql2' LoadError: no such file to load -- mysql2 from (irb):1:in `require' from (irb):1 from :0

已经提示安装了 为什么还报错？难道还有其他关联？