Re: backup versus export of db

metco_at_earth.execpc.com (Milwaukee Tool) wrote:
>
>I've been told by a Value-Added-Resaler of Oracle that if i want to backup
>an oracle 7 db, i should first do a full export, and then backup up the
>exported file.
>They said that a simple backup of the files used by oracle isn't good enough.
>The reason given went something like this,
>
> "while oracle is running, it leaves certain files open. Consequently,
> if you do a simple backup of the filesystem on which oracle resides,
> even if no db transactions are pending, you aren't guaranteed to
> capture the complete, latest state of the data."
>
>Can you shed any light on this statement? If basically true, what is really
>meant by "leaving files open"? My interest in knowing goes beyond the
>question of how to backup the db - I am also trying to decide if i there's
>enough benefit to warrant mirroring the disk partition(s) that hold the db.
>
>Thanks much for any help you lend.
>
>Jon Detert, metco_at_execpc.com, 414.783.8527
>
Before you want to make a backup of your database-files, make sure that oracle isn't running. You can do this via sqldba and the shutdown command. After that you can backup the directories where the tablespacefiles are located in.

When you export your database, only the real amount of data will be written to a file. If you use a backup solution, the maximum of bytes specified in the storage clause at the creation time of the database is taken. We work with both solutions and hadn't any problems with the consitency of data.

Regards

Christian

-- 
Christian Blaas, HP Boeblingen / Germany blaas_at_bbn.hp.com