Re: RMAN Backups/Recoveries

"Ofer Razon" <orazon_at_012.net.il> wrote in message news:brl15q$92s$1_at_news2.netvision.net.il...
> Hi All.
>
> Using Oracle 8.1.7, I am considering the use of RMAN in order to run a
> continous recovered DB, so I`ll do a full recovery once and then, every X
> days I`ll run an incremental recovery for this DB.

Do you mean recoveries or backups? If you really mean recoveries, then this isn't going to work. Once you've recovered a database, that's it: Oracle won't permit you to recover the database further. For a database to be in permanent recovery mode, it needs to be specially created as a standby database (which means mounting it with a standby controlfile).

> I know that the DB will never be "open". My actual plans are to use PIT
> disks features and open a copy of the database everytime I`ll need it,
> without ruining the recovery process.

Yikes. This is a highway to horrors. You can't do point in time recovery and not 'ruin the recovery process'. A point in time recovery means 'issue a resetlogs', at which point your database is in a new incarnation, and all prior backups and archives taken from the source database will be useless. This just isn't going to work.

>
> At first we considered using a Stand By DB, but then we`ve found that
every
> time we`ll add/resize a datafile we`ll have to do it on the standby too,
so
> we dropped this idea.

Bad move. This is the only technology that will do what you want (and even then, every time you activate the standby database, it ceases to be able to be further recovered, so repeated opening of it would mean a lot of re-cloning work to do each time.

>
> Will RMAN solve me this problem?

No.

> Do you think that it is possible to run in a "continous recovery" as I
> described?

No.

> BTW: I`m couting on the feature that every "incremental recovery" will
> update only the affected blocks in the DB and won`t create the full
datafile
> from scratch.

Irrelevant. First of all, when you perform a recovery with RMAN, you have no say over how RMAN will actually perform the recovery. It uses internal algorithms to work out the best way of effecting a recovery, and that could mean -as far as it is concerned- the quickest thing might be to restore the full backup, and then apply all archives produced since then. There's no guarantee that it will restore the full-apply the incrementals-apply last bit of archives.

Second, recovery is a process with a goal in mind: get the database back up and running. Once it's achieved that, it stops. Forever (or until your next failure).

What's your actual business problem that's led you to this suggestion? Because if we saw that, we might be able to think of something rather more workable for you.

Personally, I can't see this ever working until you upgrade to 9i Release 2 and implement logical standby with Data Guard.

Regards
HJR

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