Doing online backups (no RMAN) using snapshots / BCV Splits – alter database begin backup; split the mirror or snapshot; alter database end backup;
And… something goes wrong and the DB crashes in between the begin and end backup. You’ll get the easy to fix ora-01110 ora-10873 file needs end backup when trying to start the database back up. It won’t open and will likely still be in mount mode.
alter database end backup;