Re: Restoring from Hot Backups?

From: Dipankar <dasdipa_at_zeus.franklin.edu>
Date: 1995/10/11
Message-ID: <1995Oct11.012220.22634_at_zeus.franklin.edu>#1/1


>In article 43096, Nalini<nalini.vallampati_at_daytonoh.attgis.com>writes:
>>In article <DG6ou4.LFw_at_ranger.daytonoh.attgis.com> you write:
>>In article <4588vj$so$1_at_mhafm.production.compuserve.com> Robert Barrell
 writes:
>> Many people have posted questions recently about making hot backups, but
>>we would like to restore a tape to another machine to verify that we will be
>>able to recover from a crash should one occur. So, if anyone would be kind
>>enough to post step-by-step instructions for recovery from a hot backup, we
>>would greatly appreciate it. Thanks.
>>
>> - Rob -
>>
>>
>
>First off, I must say that it is better from an administrative purposes to have
>an occasional ( periodic ) cold backup along with the hot backup. In your case
 ,
>restore the entire hot backup and apply the online-redo logs to this database.
>Then use the command ALTER DATABASE RECOVER LOGFILE 'logfile_name'.
>This applies the redo logs on to your database, and makes sure that you
>have full point-in-time recovery. Of course, this is just the general idea.
>The details are in Chapter 19 of the Server Administrator's Guide.
>
>Nalini
>

Restoration is always dependent on the type of problem, meaning whether data file lost or log file lost or control file lost etc. In fact there could be several scenarios of recovery. Almost all of these scenariios will need to be dealt in a different way.

For example, a specific non-system data file which does not have rollback segments in it is lost. There could be 3 possible methods for recovery in this case:

	I. Using "recover database" command
	2. Using "recover tablespace" command
	3. Using "recover datafile" command

Using "recover database" .....

Step I. Restore the file lost from your backup media using

        cpio or tar etc.
StepII. Start the database without mounting it. StepIII.From within "sqldba" type 'recover database;'

	At the prompt, specify the correct filename for the archived ones if
	the suggested ones are not correct.
StepIV. After you get the message 'media recovery complete', open the 
	dataase ('alter database open;')

As recovery is a subject by itself, it is not possible to cover all the cases in few lines.

One final note - always try using 'recover ..' command over 'alter database

                 recover ..' as strongly recommended by Oracle.

Thanks,
Rajat Received on Wed Oct 11 1995 - 00:00:00 CET

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