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Re: Export every day

From: Howard J. Rogers <dba_at_hjrdba.com>
Date: Tue, 16 Jul 2002 19:32:56 +1000
Message-ID: <ah0p79$buo$1@lust.ihug.co.nz>

<peter.peltonen_at_iki.fi> wrote in message news:ah0onm$t62$1_at_oravannahka.helsinki.fi...
> Howard J. Rogers <dba_at_hjrdba.com> wrote:
>
> > So, CONSISTENT=N is usually OK, but CONSISTENT=Y is available, but
requires
> > lots of rollback space to be in use by the transactions taking place on
the
> > database during the export.
>
> How much is "lots"? Lets say I have a 1G db and a 1GHz Pentium 4 with 2G
RAM
> -- how much should rollback space I should have to export my data safely?

It is utterly impossible to give you an answer! How long does the export take? Let's say, from start to finish, it takes 1 hour. Then you need 1 hour's-worth of rollback held in the database. And how much is that? It depends entirely on the rate at which you do transactions, and the size of those transactions when you do them. So a look in v$transaction and v$rollstat might be in order.

>
> Is running exp the preferred way of backing up my data in Oracle or are
> there some other methods I should consider?
>

It's *AN* option, but it most certainly isn't the only option, nor is it the "preferred" option. You should be doing logical backups (which is what export is), certainly. But you should also be taking physical backups (ie, copies of your datafiles and control files). And that is a huge topic about which you'd best read up. Only doing the two sorts of backups covers your database against both physical loss/corruption and user error.

Regards
HJR
> Regards,
> Peter
Received on Tue Jul 16 2002 - 04:32:56 CDT

Original text of this message

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