Veritas-bu

Re: [Veritas-bu] Question on DB online backups (Wayne T Smith)

2011-09-29 11:47:02
Subject: Re: [Veritas-bu] Question on DB online backups (Wayne T Smith)
From: "Lightner, Jeff" <JLightner AT water DOT com>
To: "Martin, Jonathan" <JMARTI05 AT intersil DOT com>, "veritas-bu AT mailman.eng.auburn DOT edu" <veritas-bu AT mailman.eng.auburn DOT edu>
Date: Thu, 29 Sep 2011 15:46:56 +0000
Often enough "marginally important" becomes "critically important" only after 
it fails.  Usually that is when the admin faces the firing squad because 
management is never going to admit THEY didn't see it as important before the 
failure.

If it is important enough to backup then it is important enough to test the 
restore.   Telling folks later that it didn't seem important to you is NOT 
going to be the correct answer especially if they instructed you to do the 
backup in the first place.

The best you can do is to write an email to your management explaining the 
issues and keep a copy of it (and better yet any response) for CYA.   Even then 
it doesn't always help.  In one environment we repeatedly told management about 
lack of backup being an issue and they repeatedly let us know that they didn't 
see it as an issue.   When it finally failed the response we got back from on 
high was "You weren't forceful enough in saying it was important."





-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu 
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Martin, 
Jonathan
Sent: Thursday, September 29, 2011 10:33 AM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Question on DB online backups (Wayne T Smith)

While I agree that someone could face the firing squad if a certain
database backed critical application failed and there was no restore
capability, this may not be *that* application. Let's face it, if this
application isn't critical enough to bring in a DBA, even as a
contractor, and they didn't pay for implementation services with
backups, then this application may just be marginally important.

I would come up with and test some sort of restore scenario and set your
management's expectations. That scenario does not need to be 24x7
snapshot based point in time restore with tape backup to provide
recovery. Perhaps you take down the DB once a week to do a full, and the
expectation is that  if the database goes down you can lose up to a
weeks' worth of data. Perhaps you supplement with snapshots, or database
exports. Either way, Wayne's write-up is a great place to start.

-Jonathan

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of David
McMullin
Sent: Thursday, September 29, 2011 9:57 AM
To: veritas-bu AT mailman.eng.auburn DOT edu
Cc: WTSmith AT maine DOT edu
Subject: Re: [Veritas-bu] Question on DB online backups (Wayne T Smith)

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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