ORACLE 6 Backups

• Quoting Bgilst_at_Gmuvax.Gmu.Edu to All dated 09-22-94 ***
  > We are currently having a debate on the best way to do backups of
  > Oracle 6 at my company. We currently advise our customers to backup the
  > archive logs daily, the database(DBS file) with the database up weekly,
  > and a full export and a backup with the database down quarterly.
  

Assuming that the hot database backup is done properly (i.e., tablespaces in backup mode, force log switch, backup all archive logs, etc.) then there is no practical difference between it and a full offline backup.

In other words, your scheme seems sound. There is always room for improvement, like offsite copies, and all that sort of thing, but assuming your backups work 100%, you will be able to recover 100%.

> We have a new person in our office who is extremely headstrong, who has
> told me this procedure is WRONG, plus told me that any of the people who
> have worked on these systems in the past for our company(going back about
> 5 years) didn't know anything about Oracle. Her additional suggestion is
> to do a full export weekly.

Although a full export would be a fine additional step, it is NOT necessary, except for redundancy's sake. The only thing you gain by keeping exports is recovery if somebody blows a table away. Generally, this is not an issue.

Furthermore, a full export still requires that a database be built, and cannot provide point-in-time recovery. It is a poor substitute for the backups you are already performing.

> Her arguement is that if we have such a failure where we have to
> rebuild the database, we can go back to the weekly export.

This makes a little bit of sense, but not a whole lot. If you have a full backup of the database, you don't NEED to rebuild the whole thing from scratch, and you're doing that once a week.
> My main question is, what type of failure would it take to render > my scheme
 inadequate. We keep 3 copies of the control files, each on a
> different disk. If all 3 control files got wiped out somehow, or if
> the database crashed while updating the control files and wiped out the
> most current one, could I still recover. I believe there is still a
> difficult way to recover from this, but its not one of those things
> normally written in a book(Oracle might have to assist).

You should also be backing up the control files, of course, but control files can be built from scratch as long as careful records are kept of datafiles, etc., without requiring that a new database be built.

> I would appreciate any input or suggestions.

Although there is some merit to performing exports, and it can be a significant contributor to a backup process if a table is lost, it is not a substitute for and does not add significantly to a full database backup.

I'll have to leave you to draw your own conclusions regarding an employee who insists that everybody else is wrong without empirical backing. Received on Fri Sep 23 1994 - 17:21:37 CEST