Re: What to do with archived redo-logs ?

How long do you retain the DAT-tape backups? You need retain the log files for the same length of time.

Suppose you keep 5 generations of backups (5 days in your case). If you needed to roll back to a prior point-in-time, you would need to restore the files from a backup that completed prior to the selected point-in-time. Then you would apply all the logs from that backup up to your selected point-in-time. With 5 daily generations, you cannot rollback 6 days.

We keep multiple generations for another reason: defense in depth -- if one database restore fails, we can use the prior generation and all the logs since that backup.

MARREEL Chris wrote:
>
> First : I'm the system administrator and NOT the database administrator,
> but I'm asking myself some questions about our backup-procedureof our
> database.
> Our database runs in ARCHIVE-LOG-MODE, so it is possible to schedule
> ON-LINE backups.
> Our backup-script does the following things :
> 1) executes via SQLPLUS (as sys) an SQL-script to "ALTER TABLESPACE ...
> BEGIN BACKUP"
> 2) places all the database-files, temporary table-space, Control-file,
> redo-logs on DAT-tape.
> 3) executes via SQLPLUS (as sys) an SQL-script to "ALTER TABLESPACE ...
> END BACKUP"
> 4) Places all the archived redo-logs from the archive-directory on the
> DAT-tape, and afterwards erase all these redo-log-file (so there is
> again place enough for the next day).
>
> We execute this backup-scirpt EACH NIGHT.
>
> I was wondering, is it necessary to put ALL the redo-log-files on
> DAT-tape ?
> You can separate them into two groups :
> A) ARCHIVED-REDO-logs created between the END-BACKUP (yesterday-night)
> and the BEGIN-BACKUP (in our case this are the archived-redo-logs
> created due to the activity of the last working day)
> B) ARCHIVED-REDO-logs created while the database was in BACKUP-mode and
> the datafiles were copied one by one on DAT-tape.
>
> Which ARCHIVED-REDO-logs will be necessary to RECOVER the database in
> case of a database-crash ?
> What is normaly done with REDO-logs ?
>
> Are there people who can share their knowledge about the 'HOT' topic ?
> All information is welcome,
> Chris MARREEL.
> --
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Received on Fri Jan 02 1998 - 00:00:00 CST