OS-level Database Status/Connectivty Check (*nix)

Question

Hi all
What is the most comprehensive singular* check to monitor "running" and "connectivity" status of an ORACLE database on a Unix-like platform?
Does checking the status of SMON ps -ef | grep smon confirm both statements:
1) Database is running; and,
2) Can be locally connected using sqlplus
Or, does this require separate OS-level checks? If so, which ones?
Cheers.

Answer 1

Does checking the status of SMON ps -ef | grep smon confirm both statements:
1) Database is running; and,
2) Can be locally connected using sqlplusIf smon is running, my minimum assumption will be.....database is started in nomount state.
SQL> conn santu/santu
Connected.
SQL> conn /as sysdba
Connected.
SQL> shu immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup nomount
ORACLE instance started.
Total System Global Area 1073741824 bytes
Fixed Size                  2034376 bytes
Variable Size             264246584 bytes
Database Buffers          801112064 bytes
Redo Buffers                6348800 bytes
SQL> !ps -ef|grep smon
  ora10g 23625 23587   0 09:31:06 pts/1       0:00 /bin/sh -c ps -ef|grep smon
  ora10g 23626 23625   0 09:31:06 pts/1       0:00 grep smon
  *ora10g 23615     1   0 09:30:46 ?           0:00 ora_smon_rtest*
SQL> conn santu/santu
ERROR:
ORA-01033: ORACLE initialization or shutdown in progress
Warning: You are no longer connected to ORACLE.Regards,
S.K.