Hemant,
you said:
> The advice should be to backup online redo logs already on disk
> before beginning a restore. In fact, that is always a standing
> instruction in any Oracle Database recovery -- backup what you
> currently have on disk, no matter how badly "hosed" before you begin
>the recovery.
YAY!!!! That's a point everyone has been missing -- if you backup the
mess you have, including controlfiles, online logs, datafiles,
initialization files, you ALWAYS have a place to go back to if you mess
up a recovery.
Rachel
- Hemant K Chitale <hkchital_at_singnet.com.sg> wrote:
>
> Richard,
>
> I think that you are still missing Jared's point.
> It is quite right of you to say that a DBA should do a consistent
> backup
> and that
> one who does not run his backups properly is committing a sin.
>
> Jared has already explained two examples of why you would want the
> online
> backups
> included in a Cold Backup. And I reiterate them here.
>
> 1. On Windows, the Stop Oracle Service doesn't always do a SHUTDOWN
> NORMAL
> or SHUTDOWN IMMEDIATE. See Bug 1568668
> "With releases 8.1.5 and 8.1.6 stopping the database via the
> services, shuts the database down immediate, whereas 8.1.7
> kills the process. This means recovery is always required on
> startup and customers backup strategies my become invalid.
> If a customer takes cold backups without redo they will not
> be able to open the database. "
> So what happens if you have a database that hasn't been patched and
> you
> or your colleague or the previous DBA had been happily using the Stop
> Service
> and backing up the database without the online redo logs and one day
> you
> need to recover the database and ..... uh oh ! "Hey ! Why does Oracle
> ask for the redo log file ?!"
>
> 2. You are a consultant or a service provider or are implementing a
> system
> for a customer and ask the customer to send you a backup of his
> database.
> The SA or the trainee-DBA executes a SHUTDOWN ABORT and send you the
> database
> files [he might say "I did try a SHUTDOWN but it was 'hanging' for
> 10minutes so I
> finally killed it and ran a SHUTDOWN ABORT before backing up the
> database"]
> Always insist that the person at the other end sends you a full
> backup,
> including
> online redo logs and the init<SID>.ora.
> [Of course, instead of the other person being a customer's SA or
> trainee-DBA
> he could be your own colleague [SA/trainee-DBA/Damager] with whom you
> have
> split the
> responsibility of managing the 50 or 100 odd databases in your
> enterprise
> or the backup scripts
> may have been written by the former DBA and, although you have
> reviewed
> and verified or fixed 99 backup scripts in your first 5 days, the
> 100th
> database
> crashes on your 6th day on the job].
>
>
> I always run a switch logfile or archive log current before backing
> up archive
> logs in a Hot Backup but do not backup online redo logs with the Hot
> Backup.
> With a Cold Backup I always backup the online redo logs as well.
> [Tough luck
> for me if I join an organisation and I am the guy that got hit on
> that 6th day
> because the previous DBA's scripts weren't doing a proper shutdown].
>
> Also, although many DBAs know that you can bring up a properly
> shutdown and
> backed up cold database without the online redo logs as they know the
> OPEN RESETLOGS command, not all DBAs know this. Suppose the
> person is a trainee-DBA or an SA or a Damager. He's going to curse
> Oracle when he finds that he can't bring up his database although he
> did a "complete" backup [using the guidance provided in the 9iR2
> manual
> which so helpfully told him not to backup the online logs but he has
> never
> read about how and when to run an OPEN RESETLOGS].
>
> Therefore, the advice NOT to backup online redo logs is patently
> dangerous.
>
> The advice should be to backup online redo logs already on disk
> before
> beginning a restore. In fact, that is always a standing instruction
> in any
> Oracle Database recovery -- backup what you currently have on disk,
> no matter how badly "hosed" before you begin the recovery.
>
> Hemant
>
>
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Received on Sun May 25 2003 - 15:51:39 CDT
