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Home -> Community -> Usenet -> c.d.o.server -> Re: online backup of the redologs
The 'best' way I have found is to switch archive logs after the HOT backup is complete. Then make sure you backup all of the archive logs generated during the backup cycle.
I also backup the online redo logs, although this is not necessary. If you do not have the online logs you can issue
alter database open resetlogs;
After media recovery is complete.
Hope this helps.
Stephen C. Ashmore
Brainbench MVP for Oracle Administration
"Charles Fisher" <Charles.Fisher_at_alcoa.com> wrote in message
news:Pine.GSO.4.31.0104301254400.1366-100000_at_unknown...
> I am attempting to use standard hot-backup methods to take a complete copy
> of an instance and start it on another machine. Oracle support hasn't been
> very helpful, and I need to be certain that what I am doing is assured to
> be recoverable.
>
> If anybody can help me with this problem, I would appreciate an email copy
> as well as a follow-up post, as I don't want to miss any replies.
>
> Oracle support advised me to simply restore some redologs from an old cold
> backup and use those in perpetuity. Following this advice, I restored old
> copies of my redologs to the target, plus hot backups of all the datafiles
> from the source (and the required archived logs). When attempting to
> execute the output of "ALTER DATABASE BACKUP CONTROLFILE TO TRACE", I
> receive the following error:
>
> ----------------------------------------------------------------------
> Oracle Server Manager Release 3.0.5.0.0 - Production
> (c) Copyright 1997,Oracle Corporation. All Rights Reserved.
> Oracle8 Enterprise Edition Release 8.0.5.0.0 - Production
> With the Partitioning and Objects options
> PL/SQL Release 8.0.5.0.0 - Production
>
> SVRMGR> connect internal
> Connected.
>
> SVRMGR> @/pkg/prdcrm/backup/prdcrm.sql
> CREATE CONTROLFILE REUSE DATABASE "PRDCRM" NORESETLOGS ARCHIVELOG
> *
> ORA-01503: CREATE CONTROLFILE failed
> ORA-01229: data file 13 is inconsistent with logs
> ORA-01110: data file 13: '/pkg/prdcrm/oradata/prdcrm/platinum.dbf'
> ----------------------------------------------------------------------
>
> On the source, I then attempted to "ALTER DATABASE ADD LOGFILE MEMBER
> '/backup/redoprdcrm01.log' TO GROUP 1", then immediately "ALTER DATABASE
> DROP LOGFILE MEMBER '/backup/redoprdcrm01.log'". I did this for each
> logfile group, and attempted to use the complete set of "INVALID" logfiles
> (such logfiles appear as "INVALID" in "SELECT * FROM V$LOGFILE", and I had
> to do an "ALTER SYSTEM ARCHIVE LOG CURRENT" before I could generate one
> for the active log group) to create the redolog files on the target. Here
> is the result:
>
> ----------------------------------------------------------------------
> SVRMGR> @/pkg/prdcrm/backup/prdcrm.sql
> CREATE CONTROLFILE REUSE DATABASE "PRDCRM"NORESETLOGS ARCHIVELOG
> *
> ORA-01503: CREATE CONTROLFILE failed
> ORA-01192: must have at least one enabled thread
> ----------------------------------------------------------------------
>
> At this point, I resorted to issuing an 'ALTER SYSTEM ARCHIVE LOG CURRENT'
> on the source, ensuring that all required archived logs were copied to the
> target, then copying the online redologs *without halting the instance*.
> This worked:
>
> ----------------------------------------------------------------------
> SVRMGR> @/pkg/prdcrm/backup/prdcrm.sql
> Statement processed.
> SVRMGR> recover automatic database;
> Media recovery complete.
> ----------------------------------------------------------------------
>
> My concern is copying the online redologs in this manner. The "Oracle8
> Backup and Recovery Handbook" (ISBN 0-07-882389-7) has the following
> warning on page 94: "You should never take a backup of the online redo log
> files, as the online log file has the 'end of backup' marker and would
> cause corruptions if used during recovery."
>
> Since I have issued the 'ALTER SYSTEM ARCHIVE LOG CURRENT', I assume that
> the 'end of backup' marker is not in the 'enabled thread.'
>
> I don't want to depend upon the control file in a full restore situation,
> but it seems that I cannot create a replacement controlfile unless I have
> the redologs. Does anyone know of a better way?
>
> --------------------------------------------------------------------------
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