Re: Hot Backup Question

In article <95kq8v$klu$1_at_nnrp1.deja.com>,   humorous_at_my-deja.com wrote:
> Hey gurus
> I have a question. I have a tablespace with 6 tablespaces. They are
> being backed up inthe
> following way .
> alter tablespace tablespace name begin backup;
> cp filenum1 to filenum1.back
> alter tablespace tablespace name end backup;
>
> alter tablespace tablespace name begin backup;
> cp filenum1 to filenum2.back
> alter tablespace tablespace name end backup;
>
> alter tablespace tablespace name begin backup;
> cp filenum1 to filenum3.back
> alter tablespace tablespace name end backup;
>
> alter tablespace tablespace name begin backup;
> cp filenum1 to filenum4.back
> alter tablespace tablespace name end backup;
>
> alter tablespace tablespace name begin backup;
> cp filenum1 to filenum5a.back
> alter tablespace tablespace name end backup;
>
> Can this be a problem in the backups being consistent ?
> Do y'all see any problem with this ?
>
> Or should I go for the
>
> alter tablespace tablespacename begin backup;
> cp filenum1 to filenum1.bak
> cp filenum2 to filenum2.bak
> cp filenum3 to filenum3.bak
> cp filenum4 to filenum4.bak
> cp filenum5 to filenum5.bak
>
> alter tablespace tablespacename end backup;
>
> Is this a more preferred option ? If so why ?
>
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>

Scenario 1 is the preferred option. Scenario 2 is not preferred as it places *all* tablespaces in backup mode at the same time. Thus, it will definitely generate much more redo than in the first scenario. Also, if the database crashes during hot backup (which happened to me once) you will be forced to recover the *complete* database, as all tablespaces are marked as inconsistent.

Hth,

--
Sybrand Bakker, Oracle DBA

All standard disclaimers apply
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