When you hit DB2 errors, it is quite hard to debug those.
First the logfile is placed in $DB2INSTANCE$\sqllib\db2dump\db2diag.log
There you can find some information about your instance and maybe errors.
Second, if you encounter errors like those:
Cannot Start Database manager you should check your DB2LIBPATH or in generell your library paths, as those are properly the reason for your problem.
Login to DB2 and issue following command:
If the libpath is wrong you can update it with
db2set DB2LIBPATH=<value> -i
This will update the DB2LIBPATH in the internal registry of DB2.
Another thing is to stop a DB2 instance that is not stopping with db2stop. Issue the command db2 force application and after that a db2stop. This is quite important, as the applications are just forced down, not the db2 instance itself.
When you issued db2stop, you should not see any db2 processes in the process list besides a db2fmd process.This one is a monitoring process, also not owned by the db2owner.
To disable the Fault Monitor Coordinator, issue the command:
To stop the Fault Monitor Daemon, issue the command: