RMAN cold backup vs. hot backup

DBAs like a cold backup because the backup is consistent across the board. More than anything, they like the comfort factor of a nice, consistent backup. Hot backups will result in inconsistencies in the backed up datafiles. RMAN will resolve these inconsistencies on recovery, after a restore. For many DBAs, it is a comfort factor.

That being said, there are two areas to consider. If you perform a cold backup, you must have downtime for your database. If you cannot afford the downtime, then a cold backup is not for you. If you want or need to perform a hot backup, then you must be running in archive log mode.

Cold backups are easy, do not require archived redo logs, but require downtime. Hot backups do not require any downtime, but are a little more complex and require archived redo logs.