Re: Frequency of Hot Backups

Until you get to 9i, and DataGuard, the standby database is guaranteed not to contain every transaction that's raised in the production database -because the mechanism used to update the standby is the transfer of archive logs, and archives are only produced at a log switch. So there's always the contents of the current online log which cannot possibly have been transferred to the standby.

Now, in the event of a disaster on production, all the books will tell you to force the archive of the current log by doing an 'alter system archive log current', and then transfer that last log manually to the standby. Apply it, and voilą! No data loss. However, the chances of you being able to perform that particular miracle in the event of a true disaster is slim, at best.

So no: having a standby does *not* free you from the need to take backups of the production system. Not if you don't want to lose data. It gives you, instead, a failover mechanism that protects you from enormous downtime. It doesn't mean the production system itself is safe as houses.

As for the frequency of backups: it all depends on the frequency of transactions. If you do bulk load to a data warehouse once a week, it would perhaps be a bit daft to be doing nightly backups. If you are performing one million transactions per day, then it's perfectly possible that one backup per night would not be frequent enough.

So there's no right or wrong answer. But at a rough estimate, around 90% of the people I meet do nightly backups.

Regards
HJR

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"Ban Spam" <ban-spam_at_operamail.com> wrote in message
news:Xns91E18909E9FAASunnySD_at_68.6.19.6...


> Assume that the instance is running in archive mode.

>

> What is the frequency your organization does hot backups?

>

> If you have a "stand by" database against which you

> keep applying archived redo logfile, in theory you

> would/could/should never have to take another backup.

> Right?

>

> So what is the longest "reasonable" period between

> actual Oracle hot backups?