Re: Block Corruption, cant start DB -SOS

Fri, 20 Sep 2002 10:19:18 +0200, Candido Dessanti said (and I quote):
> > Besides, if he has no backups and no mirroring anywhere, it's
> > gonna be awfully difficult to recover anything. With or without SCN.
>
> Of course the backup have to be done, when possible.

With a multi-Tb db? It MUST be done. Not when possible.

> Do you have an idea how much takes backing up 1Terabyte database? A vary
> long time, so maybe he isnt able to do backups;

If any1 is running a multi-Tb datawarehouse db in hardware that can't back-up 1Tb in acceptable time, I can tell you there is gonna be a lot more of this sort of problem...
It doesn't take that long if the hardware is well thought out. But it can't be done on a M$/TCO shoestring budget, that's for sure.

> but the point is...if he has backups why he isnt doing a datafile
> recovery? I guess he hasnt a backup. And even with a backup success isnt
> guaranted, because it looks like there is logical corruption.

Yup. If he tries to recover and mucks it up, he's lost a multi-Tb database without appeal. At least with a backup after the disaster, he can try to recover something. I'd call Oracle support and get them to sort it out, if at all possible.

> Crash recovery is performed by database after a crash or shutdown abort
> recovering the database with the online redo logs, so idea of mine was
> simply to force an incomplete crash recovery until the transaction is
> generating the problem,even i dont think it would be successfull it wont
> damage in any way the database just because it would immediatly fail
> doing anything to database files.
>

Sure. But if he doesn't save at least the logs and controlfile prior to starting all that, he's up for some hefty problems if anything (and I mean *anything*) goes wrong during this exercise. All he needs is a typo or power failure or OS glitch half way through this and *clunk* there goes the db. Better safe than sorrow. See the stuff Howard and Richard put in their replies.

-- 
Cheers
Nuno Souto
nsouto_at_optushome.com.au.nospam