搭建oracle12c备机过程中发现sqlplus登陆报错如下：
[xdhsdb@oracle:/oracle]$sqlplus
exec(): 0509-036 Cannot load program sqlplus because of the following errors:
        0509-130 Symbol resolution failed for /oracle/app/oracle/product/12.2.0/dbhome_1/lib/libons.so because:
        0509-136   Symbol CreateIoCompletionPort (number 93) is not exported from
                   dependent module /unix.
        0509-136   Symbol GetQueuedCompletionStatus (number 94) is not exported from
                   dependent module /unix.
        0509-136   Symbol ReadFile (number 95) is not exported from
                   dependent module /unix.
        0509-136   Symbol WriteFile (number 96) is not exported from
                   dependent module /unix.
        0509-026 System error: Error 0
        0509-192 Examine .loader section symbols with the
                 'dump -Tv' command.

因为笔者之前是解压缩tar包的方式安装oracle的，都没有问题。搜索了网上都是系统相关问题
检查了iocp参数果然没有改
[xdhsdb@oracle:/oracle]$lsdev |grep iocp
iocp0      Defined               I/O Completion Ports

修改参数重启后解决问题
[xdhsdb@root:/]#chdev -l iocp0 -P -a autoconfig='available';
iocp0 changed

总结：
因为该备机的rootvg笔者是通过克隆方式拷贝过来的，虽然克隆原机参数修改了，但是克隆之后发现这个参数会被重置为默认状态。

另外一些系统参数也需要修改并重启
chdev -l sys0 -a maxuproc=16384
chdev -l sys0 -a maxbuf=500
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