-bash-2.05b$ ./emctl start agent
Oracle Enterprise Manager 10g Release 10.2.0.1.0. 
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
Starting agent ..... failed.
The agentTZRegion value in /u01/app/oracle/OracleHomes/agent10g/sysman/config/emd.properties is not in agreement with what agent thinks it should be.Please verify your environment to make sure that TZ setting has not changed since the last start of the agent.
If you modified the timezone setting in the environment, please stop the agent and exectute 'emctl resetTZ agent' and also execute the script mgmt_target.set_agent_tzrgn(<agent_name>, <new_tz_rgn>) to get the value propagated to repository.
Consult the log files in: /u01/app/oracle/OracleHomes/agent10g/sysman/log

-bash-2.05b$ ./emdctl validateTZ agent PST8PDT
tzOffset for PST8PDT is -480(min), but agent is runnning with tzOffset -420(min)
trying again after waiting for 1 sec to account for daylight transition
tzOffset for PST8PDT is -480(min), but agent is runnning with tzOffset -420(min)

查看sysman/config/emd.properties里面，时区设置的也是PST8PDT

可以用这个下面命令解决：

export TZ=GMT (用MDT也可以,PST8PDT不行,其他没尝试）

这时emd.properties里面的agentTZRegion=GMT，原先是PST8PDT.
emctl resetTZ agent
emctl start agent