Re: Help! Backup & Recovery in Oracle8 enterprise edition

Thanks to everyone for the valuable info.

We will revise our backup strategy. The Export and Cold backup method sounds great.

Jeremiah Wilton <jeremiah_at_wolfenet.com> wrote in message news:38568CC4.2D0E6AF3_at_wolfenet.com...
> TAD wrote:
> >
> > For simple backup purposes, wouldn't an export be a good idea. We do not
> > require the database to go back to say 1:35 am last wednesday. Our
> > requirement is simply to restore the database back to what it was on
> > Thursday morning. Our system is not usually used at night so we can
safely
> > shut it down.
>
> If you are willing, as you have indicated, to throw away the entire
> day's transactions in the event of a failure, then a noarchivelog mode
> database is fine. For such a situation, however, a cold backup is
> better than an export. The main reasons are that an export-based
> recovery strategy is unnecessarily complex, and takes much longer to
> perform. Cold backups on the other hand are more or less foolproof.
> Consider the work necessary to restore the database for each backup
> method:
>
> Restore to a clean host from export:
> 1. Install Oracle software
> 2. Install installation-specific configuration files: init<sid>.ora,
> listener.ora, sqlnet.ora, tnsnames.ora, etc. Hope you saved them
> somewhere.
> 3. Mount the instance and create a new database. Hope you saved a trace
> controlfile or database creat script somewhere.
> 4. Begin the full import. All actions restoring objects are performed
> through DDL and DML, one at a time. They cannot be in parallel, they
> require many operations to complete. Cross your fingers and hope there
> are no failures.
>
> Restore to a clean host from a cold backup:
> 1. Install Oracle software
> 2. Install installation-specific configuration files: init<sid>.ora,
> listener.ora, sqlnet.ora, tnsnames.ora, etc. Hope you saved them
> somewhere.
> 3. Copy backed-up files into place. Resore is performed by simple file
> copy. Many copies can be performed in parallel, and require few
> inexpensive operations to complete.
> 4. (optional) Roll forward to any point in time using redologs.
>
> > Wouldn't an export be better in this case.
>
> Why would it? Are there any redeeming features to an export for the
> purposes of recovery?
>
> > BTW, what is a "read-consistency failure".
>
> "ORA-1555: Snapshot too old. Rollback segment ... too small." This
> message occurs when a query cannot obtain a consistent read of a block
> because it has been overwritten in the rollback segments. It often
> happens to people trying to perform export-based backups on active
> systems of any considerable size. It has been covered in many previos
> threads, so a search on deja.com should turn up a wealth of information
> on it if you are interested.
>
> --
> Jeremiah
Received on Tue Dec 14 1999 - 19:12:19 CST