UNIX for Advanced & Expert Users

1) how is a hot backup performed.

i am thinking it does 1 of 2 things.
1) it exports the db and then you backup the exported files.
OR
2) you just backup the files on disk as teh db is running.


i dont need to know HOW it is done. but just the basic concept of a hotbackup. i cant find it on oracle.com.

ie: if i have a db that is 5gb. do i need another 5gb mount point for the hotbackup? or do you need a predetermind amout of space for a hot backup.

I believe the space requirements matter on what type of hotbackups you will be doing.

If you are using RMAN, then see Getting started with Recovery Manager - it shows the space needed and how to set up/decided what you would need.

Other 'home grown' scripts I've seen will either go to disk (compressing on the way so not as much disk space is needed) or straight to tape. The one constant is that the export only grabs what is actually being used from the database - it does not require the physical size unless your database is at 100%.

As far as your first question the answer seems to be " it exports the db and then you backup the exported files." is the normal way of doing it.

Your best bet is to get with your Oracle DBA and work out the needs of the application.