Dataguard Concepts

Hello All,
I have the below question concerning Oracle 11gR2 with Dataguard.
I have one primary database and one Logical standby database.
I have a question about the below scenario:
In case the primary database failed I will apply the below steps:
1. Failover to the logical standby database. Now it is reacting as a primary database.
2. I restored and recovered the failed primary database and I want to build it as a Logical standby database.
My question is, in that specific step when I restored and recovered my failed primary database, the restore and recovery process may take me two days for example, and the primary database is restored to a certain SCN, but the clients are connected to another database (the new primary) and they are modifying the data on the new primary database while i am recover my failed primary database, so when i convert my failed primary database to a Logical stand by database.
SQL Apply will automatically know from which SCN should start applying redo logs ?
These logs are applied from both archive logs of the new primary database and from the standby redo logs? since some redo logs may have been archived before overwriting.
And same question when i first create any logical standby database, i will create it from a backup copy of the primary database, so based on what the SQL apply will start applying the redo logs ?
how it can indicate that it should start applying redo logs from a certain point (or SCN)?
One more question:
During switch over: both primary and standby databases will be started up in restricted mode?
Hope my questions are clear.
Regards.
Edited by: NB on Oct 24, 2011 3:17 PM
Edited by: NB on Oct 24, 2011 3:18 PM

the result of your query is below :
Know that i used: WHERE DEST_ID = 3
is that because i defined my parameters as below?
on primary:
log_archive_dest_1       = "LOCATION=C:\app\oracle\oradata\windb\LOG_ARCHIVE_DEST_1 VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=windb"
log_archive_dest_2       = "LOCATION=USE_DB_RECOVERY_FILE_DEST VALID_FOR=(STANDBY_LOGFILE,STANDBY_ROLE)"
log_archive_dest_3       = "SERVICE=dgwindb ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=dgwindb"on standby:
log_archive_dest_1       = "LOCATION=C:\app\oracle\oradata\dgwindb\LOG_ARCHIVE_DEST_1 VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=dgwindb"
log_archive_dest_2       = "LOCATION=USE_DB_RECOVERY_FILE_DEST VALID_FOR=(STANDBY_LOGFILE,STANDBY_ROLE)"
log_archive_dest_3       = "SERVICE=windb ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=windb"
STAND_BY,   SEQUENCE#,    APPLIED,   COMPLETION_TIME
dgwindb     130     YES     10/26/2011 5:47:28 PM
dgwindb     131     YES     10/26/2011 5:47:35 PM
dgwindb     132     YES     10/27/2011 1:11:51 PM
dgwindb     133     YES     10/27/2011 1:11:52 PM
dgwindb     134     YES     10/27/2011 1:11:52 PM
dgwindb     135     YES     10/27/2011 1:11:52 PM
dgwindb     136     YES     10/27/2011 1:11:52 PM
dgwindb     137     YES     10/27/2011 1:11:52 PM
dgwindb     138     YES     10/26/2011 6:28:09 PM
dgwindb     139     YES     10/26/2011 6:35:11 PM
DGWINDB     140     YES     10/27/2011 1:12:48 PM
DGWINDB     141     YES     10/27/2011 1:12:49 PM
DGWINDB     142     YES     10/27/2011 1:12:49 PM
DGWINDB     143     YES     10/27/2011 1:12:49 PM
dgwindb     144     YES     10/26/2011 7:03:21 PM
dgwindb     145     YES     10/26/2011 7:09:22 PM
dgwindb     146     YES     10/26/2011 7:14:24 PM
dgwindb     147     YES     10/27/2011 1:12:57 PM
dgwindb     148     YES     10/27/2011 1:12:57 PM
dgwindb     149     YES     10/26/2011 7:32:29 PM
dgwindb     150     YES     10/26/2011 7:39:31 PM
dgwindb     151     YES     10/26/2011 7:45:34 PM
dgwindb     152     YES     10/27/2011 1:13:07 PM
dgwindb     153     YES     10/27/2011 1:13:07 PM
dgwindb     154     YES     10/26/2011 8:03:39 PM
dgwindb     155     YES     10/26/2011 8:10:41 PM
dgwindb     156     YES     10/27/2011 1:13:23 PM
dgwindb     157     YES     10/27/2011 1:13:23 PM
dgwindb     158     YES     10/27/2011 1:13:23 PM
dgwindb     159     YES     10/27/2011 1:13:24 PM
dgwindb     160     YES     10/27/2011 1:13:23 PM
dgwindb     161     YES     10/27/2011 1:13:24 PM
dgwindb     162     YES     10/27/2011 1:13:23 PM
dgwindb     163     YES     10/27/2011 1:13:23 PM
dgwindb     164     YES     10/26/2011 8:57:55 PM
dgwindb     165     YES     10/26/2011 9:04:10 PM
dgwindb     166     YES     10/27/2011 1:13:35 PM
dgwindb     167     YES     10/27/2011 1:13:35 PM
dgwindb     168     YES     10/26/2011 9:21:12 PM
dgwindb     169     YES     10/26/2011 9:28:16 PM
dgwindb     170     YES     10/27/2011 1:13:43 PM
dgwindb     171     YES     10/27/2011 1:13:43 PM
dgwindb     172     YES     10/27/2011 1:13:43 PM
dgwindb     173     YES     10/27/2011 12:36:29 PM
dgwindb     174     YES     10/27/2011 12:41:41 PM
dgwindb     175     YES     10/27/2011 1:13:52 PM
dgwindb     176     YES     10/27/2011 1:13:52 PM
dgwindb     177     YES     10/27/2011 1:13:52 PM
dgwindb     178     YES     10/27/2011 1:13:52 PM
dgwindb     179     YES     10/27/2011 1:11:44 PM
dgwindb     180     YES     10/27/2011 1:21:19 PM

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Doubt in Dataguard concept

Dear all,
Please help me regarding this i am very much confused.....
I had couple of doubts in dataguard concepts.
1)When archive log is transferred from primary to standby ,
a.Whether DBWR will be in active state or not in standby server.To write the contents in the archived redo log files which came from the primary to the datafiles of the standby server.
b.I am using online redo logs in the standby server not standby redo logs , whether online redologs in the standby server will have any effect in shipping of redologs from the primary database,
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Regards,
Vamsi.

Hi again,
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Online redo logs
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Create an Online Redo Log on the Standby Database
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...

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Edited by: Justin Cave on Jun 18, 2009 5:20 AM
Or more succinctly: What Hament said

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Hi!
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Edited by: DBA_Mike on Mar 27, 2009 7:22 AM

Regarding dataguard

Dear all,
Please help me regarding this i am very much confused.....
I had couple of doubts in dataguard concepts.
1)When archive log is transferred from primary to standby ,
a.Whether DBWR will be in active state or not in standby server.To write the contents in the archived redo log files which came from the primary to the datafiles of the standby server.
b.I am using online redo logs in the standby server not standby redo logs , whether online redologs in the standby server will have any effect in shipping of redologs from the primary database,
c. In my standby database online redo logs state is changing between CLEARING AND CLEARING CURRENT.How standby server redologs will change it state,
Regards,
Vamsi.

Hi Vamsi,
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Online redo logs
Every instance of an Oracle primary database and logical standby database has an associated online redo log to protect the database in case of an instance failure. Physical standby databases do not have an associated online redo log, because physical standby databases are never opened for read/write I/O; changes are not made to the database and redo data is not generated.
+...+
Create an Online Redo Log on the Standby Database
Although this step is optional, Oracle recommends that an online redo log be created when a standby database is created. By following this best practice, a standby database will be ready to quickly transition to the primary database role.
+...+

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Hi All
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Hi All
I am trying to aquaint my self with the DataGuard concepts but I must admit I have limited knowledge/exposure into this side... when I have set-up the DR so as to ship archives from the primary to disaster recovery site geographically located else where.. and that was in oracle 9i 9.2.x release..
Now there is 10g and then 11g.. and as I learn DR has evolved alot in its implementation methodologies. I am trying to fid an anecdote which can talk in a little detail/more detail but some detail less than the oracle documentation it self would be..
Honestly, when I pulled out the pdf's, I could not proceed much length... and am coming here.. for your help...
hoping may be one of you, if not most of you might have explored it well already ad might have recorded it some where in your content. If you would not mind, could you please let me know where I can get such info and then ofcourse, understand it better and quicker!!
I think to be DBA one must have patience and determination. You have to go through the document, then try yourself if anything is not in documentation and you face some problem then come to us. I got a very good link from oracle corporation. This is divided into topics, you can go one by one and ask quetions in the forum if you feel like. Check this
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Dataguard logical standby issue on lacking

we have logical standby database and its has been lacking sql apply from 14 hrs from primary database. Is there anyway i can stop sql apply and recover the database through archive files and make sync with primary and then again start the sql apply on logical standby database.
Please adivce

Neon,
I won't respond any further. The Dataguard Concepts and Administration Manual does contain a section on Troubleshooting.
It is quite clear you are using technology on which you have insufficient knowledge.
However, you belong to the class of wannabe-DBAs here,who as soon as they run into trouble start posting doc questions labeled with
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'Urgent'
or (new development) post
'Any help' every half hour, when a volunteer didn't respond to their question.
If you want a quick response, submit a SR at Metalink. At least those analists are getting paid to answer your doc questions.
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If you need the entire database to a single location ... use Data Guard.
If you need to specify tables, columns, schemas, rules, and are in a
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CPU patch procedure with physical and logical standby database in place

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Edited by: chris.baron on Dec 12, 2008 11:38 AM

Given the fact that your system is far from main-stream I'd recommend opening an SR with Oracle Support Services (metalink) and asking them.
If you would like to publish a White Paper on your experience after you have successfully completed the project let me know off-line.

Apply CPUOCT2008 with both a physical and logical standby in place

Hello All,
I'm trying to compile a decent set of steps for applying the CPUOCT2008 patch to our production RAC cluster which has both a logical and physical standby in place. I've read a tonne of documentation, including the CPU readme, DOCID 437276.1 and 278641.1. I''ve also read through the Upgrading Databases in a Data Guard Configuration chapter of Dataguard Concepts and Administration. The last doc mentioned is really for upgrading a full version of Oracle rather than applying a CPU (at least I think that's the case). DocID 437276.1 is rather sparse on details.
I guess what I'm trying to understand is the proper method for applying the patch with the logical standby in place. The physical standby looks pretty straightforward. After running opatch on it as well, it will basically have all of the changes applied to the primary shipped over and applied as per the normal primary/standby relationship. Will the same be true for the logical (having applied the patch, and then re-enabling SQL apply)? Should I aim to have it work that way? By that I mean start it up and re-enable sql apply and then upgrade the primary. Or, am I to apply the catcpu.sql script to it as well before re-enabling the sql apply? Am I wrong in regards to the physical standby as well i.e. should the catcpu also be applied directly to it?
Thanks very much in advance.
Cheers,
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Given the fact that your system is far from main-stream I'd recommend opening an SR with Oracle Support Services (metalink) and asking them.
If you would like to publish a White Paper on your experience after you have successfully completed the project let me know off-line.

Oracle streams configuration problem

Hi all,
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ERROR at line 1:
ORA-01353: existing Logminer session
ORA-06512: at "SYS.DBMS_LOGMNR_D", line 2238
ORA-06512: at line 1
When checking some docs, they told i have to destraoy all logminer session, and i verify to v$session view and cannot identify logminer session. If someone can help me because i need this sttream tools for schema synchronization of my production database and datawarehouse database.
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Thnaks for your help
regards
raitsarevo

Thanks Werner, it's ok now my problem is solved and here bellow the output of your script.
I profit if you have some docs or some advise for my database schema synchronisation, is using oracle sctrems is the best or can i use anything else but not Dataguard concept or standby database because i only want to apply DMl changes not DDL. If you have some docs for Oracle streams and especially for schema synchronization not tables.
many thanks again, and please send to my email address [email protected] if needed
ABILLITY>DELETE FROM system.logmnr_uid$;
1 row deleted.
ABILLITY>DELETE FROM system.logmnr_session$;
1 row deleted.
ABILLITY>DELETE FROM system.logmnrc_gtcs;
0 rows deleted.
ABILLITY>DELETE FROM system.logmnrc_gtlo;
13 rows deleted.
ABILLITY>EXECUTE DBMS_LOGMNR_D.SET_TABLESPACE('LOGMNRTS');
PL/SQL procedure successfully completed.
regards
raitsarevo

Convert physical standby to logical

Hi everybody!!
This is my first message on this forum, altought i have been reading few time before (around 4 months)
I have a "problem" in my database environment. I must change a physical standby to a logical standby. This cahnge is possible with dataguard technology or i must recreate the standby as logical???
thanks for your replys!!!
PD: sorry, but my english is painful (i belive) :-)

You have not really stated the Oracle version you are using, but to create a logical standby, you first create a physical one, so all you really need to do is read chapter 4 of the dataguard concepts and administration manual:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ls.htm#g105412
is the correct procedure for 10gR2

Looking for comment on disaster recovery plan

Looking for some comment on where we are and where we’re planning on going with our Continuity of Operations / Disaster Recovery plan.
Current setup is Oracle 10.2.0.2.0 on HP-UX Itanium 64-bit. OAS / Forms 9i on a separate HP-UX Itanium box. We do not have control over the version of Oracle or the hardware. I am pushing the powers that be on upgrading to 10.2.0.4, but am not holding my breath.
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Since sister site is a couple of hours away and crosses major network boundaries, management would like to also put up a DataGuard standby at a facility only 30 minutes away and within our own network. Plan is to host that on duplicate HP servers, but disk would be on a NAS instead of a SAN.
I have managed a DataGuard setup, but did not create/configure it, so am now digging into the docs, starting with the DataGuard Concepts. I’ve never worked with NAS and am not clear on how it differs from SAN, and what the implications are.
I'm looking for any comment, especially any red flags, on what I’ve described.

Satish Kandi wrote:
Not an expert comment on your setup but just the thoughts that came to my mind while reading this...
1. What is the setup for backup preservation? Is it in one of the servers only? Is the backup also replicated?Belt and suspenders. The backup location on disk is part of what gets mirrored to the sister SAN. Plus, the nightly system backup to tape picks it up as well.
2. What about OAS/Forms 9i backup? You have not mentioned anything about that.That is also mirrored to the sister SAN.
3. What is the archive log generation frequency? Or how much data loss can you afford?A typical day will see one or two dozen archivelog files.
>
In addition, a daily full-system backup (to tape) is done with the db shut down, providing a daily cold backup as well as backup of the online backupsLucky you :-) but I don't see a need for this with the levels of backup that you have (especially with RMAN weekly backup and daily archive log backup). No, no need, but it does give us another layer at no real cost. This cold backup is really just a byproduct of a daily full system shutdown and backup. We have a high tolerance for system down time, but low tolerance for data loss.

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