Linux的yum install 不能用并行的方法去运行

我之前不知道yum install 不能用并行的方法去运行

（此处说的并行是开多个secureCRT同时去运行yum install，也就是说：只能一个yum install一个 yum install的运行），于是就有了下面的报错：

如下的环境是RHEL6.5 X86-64bit

[root@hostb dev]# yum -y groupinstall Desktop
Loaded plugins: product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Existing lock /var/run/yum.pid: another copy is running as pid 9237.
Another app is currently holding the yum lock; waiting for it to exit... --------------->>>>注意此处的提示
  The other application is: yum
    Memory : 148 M RSS (463 MB VSZ)
    Started: Sat Jan  2 12:48:04 2016 - 01:05 ago
    State  : Running, pid: 9237
Another app is currently holding the yum lock; waiting for it to exit...---------------->>>>每2秒重复一次
  The other application is: yum
    Memory : 148 M RSS (463 MB VSZ)
    Started: Sat Jan  2 12:48:04 2016 - 01:07 ago
    State  : Uninterruptible, pid: 9237
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory : 148 M RSS (463 MB VSZ)
    Started: Sat Jan  2 12:48:04 2016 - 01:09 ago
    State  : Uninterruptible, pid: 9237
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory : 148 M RSS (463 MB VSZ)
    Started: Sat Jan  2 12:48:04 2016 - 01:11 ago
    State  : Uninterruptible, pid: 9237
^C

Exiting on user cancel.
[root@hostb dev]#