I am starting on Oracle, and notice that our cold backup has a interesting feature. It starts at 2:00 am and end around 2:40 am, but when I look into instance configurations, DB has started at 2:01 am.
Is this correct and is the cold backup done on right way??
You should look at your backup log and see what Oracle files have been skipped. I would guess that your database is starting to soon and that you are not really backing up your database. You need to find out how long it takes to backup your database and allow enough time for that to happen. You should be monitoring you backup log for any errors or skipped files that might indicate a problem. i.e. If your backup is skipping the system datafile everyday then you don't have a reliable backup.
You can do an export everyday. I think of an export as a safety net. I wouldn't want to have to restore from it, but it is nice to know I have it. When you restore from an export you restore to the time the export was taken. If you are in archivelog mode, and you should be, you can in theory restore up to the point of failure.
You don't have a valid backup, until you have a valid test of your backup on another system.
IŽve looked into my log file and no one of my datafile have been skipped, and close and open operations on DB are without errors or warnings.
IŽm upset only because this close/open interval is so short, no more than 40 seconds, and i am affraid this cause me some problems in future. By now, I am able to recover my backup with no problems!!
My DB is 3 GB size.
And your suggestions about export, I use this procedure like a alternative way of backup, Žcause, like you, I like to work with EXP/IMP, although is say that exp/imp isnŽt a secure way to do backup. Anyway, thanks by it!!
My questions stands: Is normal my close/open time be so short?? Or am i worried without significance?
If you are really concerned schedule a bcakup on a weekend and watch it backup. Maybe you DLT tape drive is so fast is backup up the entire database in 40 seconds and everything is peachy. You can certainly find out.