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Home -> Community -> Mailing Lists -> Oracle-L -> RE: RMAN Repository vs. Controlfiles
Thanks Bruce,
So it looks like the only feature that does not have an alternative solution is the stored scripts. You can backup the controlfile and keep the logs to cover everything else.
-----Original Message-----
[mailto:Bruce.Reardon_at_comalco.riotinto.com.au]
Sent: Tuesday, June 19, 2001 5:31 PM
To: Multiple recipients of list ORACLE-L
Steve,
>From the 817 documentation on RMAN:
"
Storage of the RMAN Repository Exclusively in the Control File
Because most information in the recovery catalog is also available in the
target database's control file, RMAN supports an operational mode in which
it uses the target database control file instead of a recovery catalog. This
mode is especially appropriate for small databases where installation and
administration of another database for the sole purpose of maintaining the
recovery catalog is burdensome.
Oracle does not support the following features in this operational mode:
Stored scripts
Restore and recovery when the control file is lost or damaged
Types of Records in the Control File
When you do not use a recovery catalog, the control file is the exclusive
source of information about backups and copies as well as other relevant
information. The control file contains two types of records: circular reuse
records and non-circular reuse records.
Circular Reuse Records
Circular reuse records contain non-critical information that is eligible to
be overwritten if the need arises. These records contain information that is
continually generated by the database. Some examples of information circular
reuse records include:
Log history
Archived redo logs
Backups
Offline ranges for datafiles
Circular re-use records are arranged in a logical ring. When all available record slots are full, Oracle either expands the control file to make room for a new records or overwrites the oldest record. The CONTROL_FILE_RECORD_KEEP_TIME initialization parameter specifies the minimum age in days of a record before it can be reused.
See Also:
"Monitoring the Overwriting of Control File Records" to learn how to manage
Oracle's treatment of circular-reuse records.
Non-Circular Reuse Records
Non-circular reuse records contain critical information that does not change
often and cannot be overwritten. Some examples of information in circular
reuse records include:
Datafiles
Online redo logs
Redo threads
Recovery Without a Catalog
To restore and recover your database without using a recovery catalog,
Oracle recommends that you:
Use a minimum of two multiplexed or mirrored control files, each on separate disks.
Keep excellent records of which files were backed up, the date they were backed up, and the names of the backup pieces that each file was written to (see Chapter 4, "Generating Lists and Reports with Recovery Manager"). Keep all Recovery Manager backup logs.
The current schema of the database.
Which files were backed up.
When the files were backed up.
The names of the backup pieces containing the files.
See Also:
"Understanding Catalog-Only Command Restrictions" for a complete list of
commands that are disabled unless you use a recovery catalog.
"
Regards,
Bruce
-----Original Message-----
Sent: Wednesday, 20 June 2001 2:02
To: Multiple recipients of list ORACLE-L
With Oracle 8.0 there was RMAN functionality that you could only get by having a repository in a database. But with Oracle 8.1 it seems that you get all the functionality you need with controlfiles. What functionality do you lose by using RMAN with controlfiles?
Steve Orr
-----Original Message-----
Sent: Monday, June 18, 2001 2:11 PM
To: Multiple recipients of list ORACLE-L
You can just use the controlfile so you don't have to setup a database repository. Here's a clip from page 2-8 of the User's Guide:
"When you use a control file as the RMAN repository, RMAN still functions very effectively. If you choose not to use a recovery catalog, follow the guidelines in "Managing the RMAN Repository Without a Recovery Catalog" on page 3-45. Specifically, make sure you understand which commands require a catalog, and develop a strategy for backing up the repository."
You can configure the amount of history kept in you controlfiles with the
following init.ora entry:
# Keep 14 days of history in the control file for the RMAN backups...
CONTROL_FILE_RECORD_KEEP_TIME = 14
Of course, make sure you backup the controlfiles. :-)
Steve Orr
-----Original Message-----
Sent: Monday, June 18, 2001 9:17 AM
To: Multiple recipients of list ORACLE-L
I've logged a TAR on this one with Oracle. They have verified what I suspected all along. The SAs here don't understand how Oracle performs a hot backup. There is no difference between raw and cooked file systems as far as Oracle is concerned when performing a hot backup. Also, the skipping of the header is only applicable to certain variants of UNIX.
One other question here. Does anyone have recommendations on the repository database required for RMAN? Do we need to keep a separate instance on another production box? Or the same production box? Does everybody have all of there repository information for all of their database in one instance? It seems like you would want a separate instance for each repository and have them staggered across different machines so that the odds of losing your database and it's repository at the same time would be low. Any suggestions?
Thanks for all the replies so far!
--Michael
-----Original Message-----
Sent: Friday, June 15, 2001 9:55 PM
To: Multiple recipients of list ORACLE-L
Michael,
We use RMAN on RAW with EDM (EMC) backups, without any problem. When using
RMAN, it will take care of all blocks that are being changed while the
backup is
going on. Also as EDM interfaces with the Tape library, RMAN will write
directly
to the Tape . Have this set up on about 15 databases and all of them are
working
fine. But occasionally our backups fail on 8.1.6 databases due to lack of
resources on the Server (and some bugs!).
Rama
"Jenkins, Michael" wrote:
> We have parallel server running on on a Sun Cluster 2.2 and we are looking
> for the easiest way to perform hot backups. Now, I know that you have to
> use the "dd" command and skip the header at the beginning. Everything I
> read on metalink indicates that you can use basically the same paradigm as
a
> hot backup on cooked file systems. But, the sysadmins here tell me that
the
> raw device can't be backed up if there is any write activity on the data
> file that is currently being backed up. Now we all know that contrary to
> popular belief there is write activity on a data file even when the
> tablespace is in backup mode. Is "rman" or some other block-level backup
> utility the only way to get a reliable hot backup on raw devices? Does
> anybody have any experience with hot backups that are made while the
> database still has active users logged in?
>
> I look forward to everyone's thought on this.
>
> Thanks.
>
> Michael L. Jenkins
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Reardon, Bruce (CALBBAY) INET: Bruce.Reardon_at_comalco.riotinto.com.au Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Orr, Steve INET: sorr_at_rightnow.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Tue Jun 19 2001 - 18:16:34 CDT
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