Re: ORACLE data block corrupted

From: Howard J. Rogers <howardjr_at_www.com>
Date: Mon, 2 Apr 2001 19:09:20 +1000
Message-ID: <3ac841d8@news.iprimus.com.au>

"Dino Hsu" <dino1_at_ms1.hinet.net> wrote in message news:74ofctkitftdbhnqhpfonk17eikradlm1i_at_4ax.com...
> On Sat, 31 Mar 2001 14:42:39 +0200, "Sybrand Bakker"
> <postbus_at_sybrandb.demon.nl> wrote:
>
> >
> >Datablock corrupted means there is an error on your disk.
> >For now: you were lucky it is a rollback tablespace.
> >Create an extra rollback segment in the tablespace system, drop the
 rollback
> >tablespace, bringing the other rollback segments offline first of course,
> >shutdown the database and make a backup (with verify!)

                                                          ^^^^^^


> >Now remove the affected file

> >Now check the disk

> >If all is OK the bad spot doesn't belong to any file.

> >Bring up the database and recreate your tablespace.

> >And yes of course you will need to run upgrade scripts.

> >

> >Hth,

> >

> >Sybrand Bakker, Oracle DBA

> >
> >
>
> Sybrand & Howard,
>
> I appreciate your help very much because they are very helpful. I
> would especially appreciate your in-time correction when I forgot
> something I have learned in the DBA 1A class. The recovery part is
> really a challenge to me.
>
> Here I have one more question:
> Can you tell me the exact meaning about a backup with verify? I know
> some backup procedures, but I am not sure which is the one you mean:
> 1.export with exp80.exe
> 2.ArcServe with Oracle Option
> 3.Recover Manager
> I like exp80.exe because it can be run when the database is open, and
> we have more control on the objects we backup, but it seems you don't
> mean exp80.exe.
>

I never think of export really as backing up the database -you certainly can't recover all your data using it. It's a relatively cheap and good way of recovering from the dropping of objects without the hassle of an incomplete recovery, but it shouldn't be your primary backup technique if recovering all data is a requirement.

As for 'backup with verify', there are a couple of approaches. If you use Recovery Manager (which also allows control over what datafiles get backed up, and can do backups whilst the database is up and running), then the verification is implicit -if rman encounters block corruption, you'll know all about it pretty quickly!

If you are doing old-fashion backups using operating system commands, then there is a utility, dbverify, which can be run against all the backup copies of the datafiles, and that will show up any corruption very quickly too. The unix command to run the utility is 'dbv'. I imagine in NT version 8, it was probably 'dbv80'. (It can also be used on datafiles which are in use).

Haven't a clue about ArcServe, I'm afraid. Never used it.

Regards
HJR
> Regards,
> Dino
>
Received on Mon Apr 02 2001 - 04:09:20 CDT