Back from a week vacation and found that the database is not working as well the ORCLE EM. What a pity for me as a newbie DBA without any mentor or help inside office. The good thing is I have Intenet to look for help....
OK, after half day working around, here I record the steps after server is accidently shutdown:
1. my bad is not setup swap space persistent, so I have to swap -a to make enough space, will do the persistent setup for swap space.
swap -a /export/home/oracle/orcl_swap then swap -l to check
2. Start the listener: lsnrctl start
3. Set up the ORACLE_SID, could add the line in .profile: export ORACLE_SID=orcl
4. Set up the ORACLE_HOSTNAME and UNQNAME for ORALE EM
OM will look inside folder solaris_orcl
5. Startup database
sqlplus / as sysdba then startup
6. Start Oracle EM
emctl start dbconsole
Thanks to the link ORACLE-BASE.com: