What happens in header datafile, control file, redo log file when begin backup and end backup i issu

Hi There,

In our environment, we use SMO ( snapmagare for oracle) to do a backup of the volumes where all oracle's files are hold.

SMO uses : begin  database backup and end database backup to perform a backup.

What happens in header datafile, control file, redo log file when begin backup and end backup i issued? In other words, which scn are written in these files when these comands are given?

Our layout  where Netapp storage is used is as follows :

In  VOLUME1, are present all datafiles

In VOLUME2 , are present all control files, online redologs and archived_logs

During backup, snapshot of both volumes  are taken.