oracle创建实例提示主机名不能有下划线并且不能超过32个字符
EMCA stops with "Hostname should not contain underscore _ in it and it should not be longer than 32 characters" [ID 1265731.1]
Applies to:
Enterprise Manager Grid Control - Version: 10.2.0.4 to 11.2.0.2 - Release: 10.2 to 11.2
Information in this document applies to any platform.
10.x和11.2.x版本都存在这个问题，主机名一定不要加_线,加的话，会带来很多莫名其妙的问题
解决方法：
1、去掉主机名中的下划线，长度别超过32个字符
2、修改oracle用户环境变量增加：
export ORACLE_HOSTNAME=HOSTNAME3、修改/etc/hosts文件增加主机名对应的本机IP解析，如
192.168.121.127 dev127