Re: Backup Sanity Check

> All subsequent runs will apply the incremental to the image copy,
> bringing it up to date.

You can test this for yourself....take an incremental level 0 backup. Note the file size and timestamp of the backup piece. Then incorporate some changes to the database. Take an incremental level 1 backup. Now look at the backup pieces from the level 0 backup. Did the file size change? Did the time stamp change? I can tell you this....the BACKUP INCREMENTAL command does not change the image copy.

Now looking closely at your BACKUP INCREMENTAL command, what you are performing, and where the confusion comes in is that you are also employing the FOR RECOVER OF COPY WITH TAG option. This option is new to Oracle 10g (AFAIK) and is called Incrementally Updated Backups. This is different than the regular incremental backups which both I and Frank are talking about. This is a subtle distinction which I missed the first time around.

One point to note about the Incrementally Updated Backups is that you need space on disk for image copies of your database. For my large databases, that is not an option. My backups go to tape and RMAN will apply incremental level changes to the image copy on disk. The disk space required to hold your backup may or may not prevent you from using this feature.

Now take a look at section 4.4.3.2 of the document you referenced. In that section, I quote the following:

"the RECOVER COPY... UNTIL TIME statement applies the level 1 incremental from seven days ago to the copy of the database. The BACKUP INCREMENTAL... FOR RECOVER OF COPY statement creates an incremental backup containing the changes for the previous day."

So that tells me that you have an image copy of the files AND you have an incremental level 1 as well. When you perform the RECOVER COPY command it merges the incremental level 1 taken yesterday with the image copy, making the image copy a 'snapshot' of the database as of yesterday. Then you take an incremental level 1 today. So should you need to restore, RMAN uses the image copy as of yesterday, the incremental level 1 taken today, and at most 24 hours of archived redo logs to bring the database up to the current point in time.

It is the RECOVER COPY command that merges the incremental level 1 contents with the image copy, not the BACKUP INCREMENTAL command.

HTH,
Brian

-- 
===================================================================

Brian Peasland
oracle_dba_at_nospam.peasland.net
http://www.peasland.net

Remove the "nospam." from the email address to email me.


"I can give it to you cheap, quick, and good.
Now pick two out of the three" - Unknown