Re: Different backup procedure.

Hot backups can only be performed while the database is open and running in archive log mode...more on archive log mode in a minute...

A hot backup is performed while the database is running, it is never shutdown which is done for different reasons some of which include around the clock system use, telephone companies for instance. The other obvious advantage is that the shared pool does not get flushed.

Archive log mode: this is the process of making a copy of a redo-log, once it has filled up or a checkpoint is made. Redo-logs get over-written so if you ever wanted to recover a database to a point in time and it is not running in archive log mode you're out of luck....

A data warehouse is a common spot for a database to NOT be running in archive log mode...Any other type of transactional database normally always operates in archive log mode..

The hot-backup process, in a nut-shell, places each tablespace, one at a time, into backup mode('alter tablespace SALES begin backup;') you then proceed to take a copy of data files associated with that tablespace. Thte tablespace is then taken out of backup mode('alter tablespace SALES end backup;'), and the next tablespace is processed. You will also have switch log file('alter system switch logfile;') after every tablespace..
Note: The system tablespace is the last one to be done...

During recovery you restore all the datafiles and then roll the database forward using all the archived redo-logs generated since the hot-backup.

I hope this has atleast given you an overview of the hot-backup..Before implementing please pickup an good Oracle Book on Backups, Oracle Press has a few good ones, and read up on it all you can.

Good Luck and contact me via e-mail shoud you need more info....

Regards,
Robert Prendin

"giau45_at_yahoo.com" <giau45_at_yahoo.com> wrote:

>I keep reading on Oracle backup procedure. And I'm still fuzzy about
>hot backup and archive mode.
>
>Cold backup: shutdown all DB and do a complete copy of dbf files (as I
>understand it)
>
>How is backup work and archive log mode work ? Thank you.
>

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