Wayne - You are looking at this from the wrong perspective.
You need to be concerned about RESTORING your data.
It does not matter how 'successful' your backups are if you cannot restore the
data.
IMHO you really need to get a DBA or 'someone' to sign off on your backup
procedure, as well as test your restore, otherwise you are setting yourself up
for a "resume generating event"...
------------------------------
Date: Tue, 27 Sep 2011 11:45:35 -0400
From: Wayne T Smith <WTSmith AT maine DOT edu>
Subject: Re: [Veritas-bu] Question on DB online backups
To: veritas-bu AT mailman.eng.auburn DOT edu
Message-ID:
<CAEgY-F6eSLSi=X0JJgFJ9bf1KeY3jzjtZqDq2ztb_61oF25eJw AT mail.gmail DOT
com>
Content-Type: text/plain; charset="iso-8859-1"
Ouch, having an Oracle database without a DBA is like having NetBackup
without anyone that knows NetBackup.
There are several ways to do backups of Oracle databases. These include
- Cold, full. You take down the database and backup all associated disk
space (data, redolog, and perhaps other types).
- Cold backups do not require Oracle archivelog mode.
- Restoration requires database down or restore to essentially
identical setup on a like machine.
- Restoration is to back to the time of your backup.
- Note for all backup types: Your file system backups will exclude
Oracle managed, as a file system backup of an online Oracle database is
insufficient for recovery. Your file system backup should include the
Oracle software home and certain other objects (control files, inventory,
oraInst.loc, etc) ... not sure where these are on Windows.
- Cold, RMAN level 0 and 1. You write a script that brings the database
down, use RMAN to back it up, then start the database again.
- Note for all RMAN backup types: RMAN is simply the Oracle utility to do
backup and restore.
- Whereas the above backups were simply of file system disk spaces
while the database is down (perhaps using NetBackup or a disk
copy utility),
RMAN decides what data to copy, where to put it and keeps
track where it has
put the backup files.
- RMAN writes its backups to disk or tape. While it is possible to
have RMAN write to disk and then have NetBackup backup the
file system data,
this is awkward and restoration goes from a simple, automatic
process to a
time-consuming very difficult process if NetBackup has the data.
- The Netbackup solution is to purchase a license that includes the
Oracle Agent. This is a shim that gets installed in the
Oracle software
home. RMAN thinks it is backing up to tape (device type
"sbt_tape"), but
the shim captures the RMAN data and sends it on to your
backup server. It
doesn't matter if your backup server uses disk or tape ...
everything back
at the backup server is transparent to RMAN ... just like
NetBackup file
system backups.
- Just like file system cold backups, you need to verify and
practice various restore scenarios. RMAN gives you a much
better chance to
do the restore you need (and have the necessary backup
objects available).
- RMAN keeps track of the stuff it backs up. It has two methods.
RMAN will put information about its backups in the Oracle
database control
files. RMAN also has a "catalog" feature, which means its backup
information is stored in a database someplace. If you use
the RMAN catalog,
your restore scenarios are substantially enhanced. Using an
RMAN catalog is
NOT required by RMAN nor the Oracle Agent.
- RMAN has its own retention schemes. Now you have 2 retentions to
worry about ... if either the RMAN retention or the NetBackup
retention
period expires, your backup data is lost.
- Hot - Hot backups are taken with the database online. Hot backups
require archivelog mode set in the database, which means that
changes to the
database, as recorded in the redologs that any Oracle database has, are
copied to archive redo logs. Archivelog mode along with database backups
allow one to restore/recover to a point in time of your choice
(that is, all
committed changes at any point in time). Depending on your requirements,
these archive redo logs must be saved for as far back as you
might wish to
do a restore.
- Hot backups do not require RMAN. One may put an Oracle tablespace
(collection of related data files) in backup mode, backup (by
disk copy,
NetBackup user backup, or whatever) and then remove backup
mode. While this
can be done I strongly suggest you don't, for I predict you
will not be able
to do the restore you want one day.
- RMAN is the tool of choice for hot backups. Again, backup may be
to RMAN disk or tape.
- I backup many databases using the NetBackup Oracle Agent.
With an appropriately written script to control the
backups, once can invoke
a backup on the client as well as having scheduled
Netbackup backups. These
backups have several setups you must perform:
- Write or find a working script
- setup RMAN configuration
- setup NetBackup server configuration
- In addition, depending on your NetBackup version/platform,
you may have to install the Oracle Agent separately
from the NetBackup
client (older versions only, I think) and you may have
a configuration step
to link the Oracle Agent into the Oracle software home
(one does on Linux
and Solaris)
- I backup many database directly to disk, where the disk is an
NFS (CIFS in your case) share on a de-dup disk storage
appliance. This is
also my future direction. Pros include no Oracle Agent install and
licensing (nor NetBackup, for that matter!) and simpler problem
resolution(NetBackup status codes are not sufficient for
backup success);
cons include no NetBackup scheduling and NetBackup or StorageScape
reporting. One must script or periodically manually check
that backups are
being done.
So, if you have an Oracle DBA, you really want her intimately involved in
backups.
The above describes the case with database on standard disk. If you use
oracle ASM, you really need a DBA, IMHO.
The above does not discuss the flashback, formerly fast recover area and its
relationship to more comprehensive backup and recovery ... something that
can be very useful to quick database recovery.
The above does not discuss the export/import and data dump utilities that
may have a place in backup and recovery of your database.
I hope it helps, though! ;-)
Cheers, Wayne
On Mon, Sep 26, 2011 at 1:33 PM, WEAVER, Simon (external) <
simon.weaver AT astrium.eads DOT net> wrote:
> **
>
> Hi, this is really for anyone doing online Oracle Backups?
> Trying to create a new policy for this. Got agent installed (licensed).
> Environment all Windows 2003.
>
> All I want is to do an online Oracle Backup. But I am struggling with this,
> as I have no DB Support.
>
> Being told that backing up Oracle is huge excercise and needs time. Trouble
> is, I wasnt expecting this sort of response.
>
> Does anyone have advise or a script or something I could try and use to
> perform an Oracle Backup?
>
> At the moment, I stop services, then do backup & start services. But Im not
> sure that is good practice. while Oracle Down, application is down. Hence,
> no one works!!!
>
> Any input appreciated. I have and am still using Admin guide, but I wanted
> real world advice here. I got a sample Hot Oracle DB Backup from the goodies
> directory, but not sure if this is right way to do it.
>
> Goal is to get a backup while application online. I do tons of online SQL,
> and no issues with backups..... Yet apparantly Oracle is more complex !!!
>
> News to me... But feedback welcome
> Thanks
>
> *Regards*
>
> *Simon** *
>
>
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