server down in the middle of hot-backup.

Today Morning, I had a very touch time with my DB.

I thought of taking hot-backup, because, number of users accessing the db will be less on morning.

I've started the hot backup.

It was going well, until the system tablespace's turn.

When the system tb is offline for hot backup, the server went down, without any hint.

Later I got to know there was a problem in UPS.

Within few minutes, the server started again. Now, my tough-time started.

Upon starting the db, I got "ORA-10873".

I've mounted the db, and checked v$backup, v$datafile views for datafile's status.

The system tablespace and it's datafiles were offline.

I issued "alter database datafile '' online"  for all the system*.dbf files. The sql went fine.

But still, status for system datafiles were showing "active" in v$backup view.

Tension mounting as I got calls from client-side about the db.

any guess....?

Referred "http://www.oracleabc.com/oracledocs/11gErrors/ORA-10873.htm"

I re-issued "alter database datafile '' end backup". 

Now v$backup shows 'Not Active'.  Really sucks.

why my previous sql failed to bring back the dbf from offline ?