RE: Inheriting a "interesting" recovery process

Hello whoever you are (you forgot you sing your email)...

An export is only good as a last resource when everything else fails...
or when you want to migrate a schema to another database and stuff like
that.

Your very best friends are:  'Cold Backup' (hot whenever you can't do
colds) and make sure your database is in archivelog mode if you want
full recovery...

If your database stores traffic tickets, then keep doing whatever you're
doing ;-)

Thanks.

Abraham Guerra
Oracle DBA
American Family Insurance

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of stv
Sent: Thursday, August 03, 2006 6:35 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Inheriting a "interesting" recovery process


Greetings all,

Summary
=======
I'm a newbie Oracle DBA in a new job [non-profit in a small town, life
is like that sometimes ;-) ]. I'm busting my butt reading up on
everything I can, but there is one issue that I want to understand
immediately: RECOVERY. Right now, we are covered only by a nightly
export using the EXP utility. Archived redo logs exist, but are not
backed up.

Exactly how much data do we stand to lose? My guess is anything that
happened after the export (i.e. the redo logs don't help much as
things stand), but I'm not sure of that.

Does EXP have read consistency like a normal select? Or will there be
some gray areas in the dump file if open transactions existed at the
time of export?

Details
======
We are running Oracle 9.2.0.6.0 64bit on Solaris 8. However, the
database has evolved since 1993 (starting, I believe, with Oracle
7.?), living through several front-end applications. There was one DBA
for most of those years, self-taught, and one short-term guy before me
(he lasted less than a year).

The nightly dump file is copied to an offsite machine, a local machine
and, once a week, tape. There is only one copy of the archived redo
logs (on a separate disk from the datafiles). These logs are not
copied off the production machine at any time. The control files
appear to be saved on a variety of disks, but are not copied off of
the machine.

As I understand things, this is odd. Having archived logs is a Very
Good Thing, but I read everything to say they are intended to be used
with an official hot backup (i.e. ALTER TABLESPACE xyz BEGIN BACKUP).

Given that we are already in archived log mode, I think I have a basic
understanding of where things need to go, using the proper hot backup
commands, having more copies of the redo logs & such. But that's
another post.

Right now I'd like to make sure the Powers That Be understand where we
are and why I'm gonna be busy on something they perhaps thought was
solid. I intend to start testing the recovery process ASAP ... is it
even worth testing the current system?

Configurations
===========
The export command:

exp USERID=system/secret BUFFER=30720 \
        GRANTS=Y ROWS=Y COMPRESS=Y \
        INDEXES=Y CONSTRAINTS=Y FULL=Y \
        CONSISTENT=Y STATISTICS=none

Some relevant init.ora settings:

# ARCHIVE
log_archive_dest=/u07/oradata/SID/archive
log_archive_format=arch_%t_%s.arc
log_archive_start=TRUE

#FILE CONFIGURATION
control_files=("/u02/oradata/SID/control01.ctl",
"/u03/oradata/SID/control02.ctl", "/u04/oradata/SID/control03.ctl")


Resources
=========
Saw this 2004 thread:
http://www.freelists.org/archives/oracle-l/06-2004/msg02261.html

Scanned stuff here:
http://www.orafaq.com/faq/backup_recovery
--
http://www.freelists.org/webpage/oracle-l
--
http://www.freelists.org/webpage/oracle-l


Other related posts: