Hot backup and redologs

[Samuele]

Hi all, i have a question. After an hot backup i must keep my archived redo log or can i delete averything? I must back up them? If yes, why if i have a complete copy of my db done with the hot backup?
Thanks, any answer will be very appreciated.

Samuele

[DBAtrix]

A hot backup is by definition inconsistent. Archived redologs reconcile this inconsistency. You will need (at a minimum) all the archived redo logs from the time just before the backup of the first date file to the time of the backup of the last datafile. (i.e. if it takes you 3 hours to backup all your datafiles, you will need all redo info for the entire 3 hours). It is a good practice to archive the current log immediately after your backup, and then backup your archived redo logs.

Why keep archlog backups? If you ever have a bad datafile backup (it happens alarmingly often), having all the archived redo logs can allow you to go back in time indefinitely. You are only limited by the completeness of your archlog backups and allowable recovery time.

If you took a good cold backup (including on-line redo logs), then you would not need archived redo logs. That backup would be consistent to a point in time (same SCN).

HTH, D.