Re: Cold & Hot backup!

"OracleMS" <lostpwds_at_hotmail.com> wrote in message news:17742ed1.0107131246.5dc5274a_at_posting.google.com...
> If I do a cold backup every week, I dont need to store
> hundreds of archivelogs from the past 6 months. I think everybody
> would agree that after a cold backup, you can delete all the archives
> generated before the database was shut down, since at the point of
> shutdown, checkpoints make sure that the controlfiles and datafiles
> are consistent. Mixing hot and cold backups in your backup strategy is
> actually a good thing and storage needs DO differ depending on the
> type of backups for the reason I mentioned above.

The storage needs don't differ, by very much, between hot and cold backups in your scenario above.

In cold backup mode you need the datafiles, control files and any subsequent archive logs as you state above.

In hot backup you need the datafiles, controlfiles and any subsequent archivelogs (plus the redo generated whilst the tablespaces are in backup mode).

The rule is the same you only need the redo since your last backup ( hot or cold makes no difference.) In fact the only difference is that there will be more redo from a hot backup for two reasons. 1 work is still going on (doh) and 2. the redo for the work in one records whole block images not just data changes.

--
Niall Litchfield
Oracle DBA
Audit Commission UK

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