Why are all sessions used by SYSMAN? I hope I can find some help with an issue in Oracle 11g on Windows 2008.  We've done a system copy by copying the datafiles from backup, and recreating the control files, and the database is up. However, within an hour or so, all sessions become taken by SYSMAN. We've found that stopping the dbconsole (emctl stop dbconsole) will terminate them. Is there something I should do to refresh dbconsole, or delete and recreate the configuration?
You mentioned system copy. Whenever you change the ipaddress or hostname, DBConsole goes haywire, and even the official solution is to recreate it as described in:

How to configure Dbconsole After the Ipaddress or hostname of the Machine has Been Changed or if the hostname ipaddress is going to be changed? (Doc ID 1333938.1)

The usual steps to do this:

emca -deconfig dbcontrol db -repos drop
emca -config dbcontrol db -repos create