Downtime for logical or physical standby database

Hi ,
Are there any downtime required to refresh the data from the primary database to logical standby or physical standby database. What are the pros and cons of
using logical and physical standby database approach. which one is advisable to use in production environment.
Regards,
Richard

Hi Richard,
I'd suggest you read the documentation as a starting point, to answer your questions on here would be quite lengthy,
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/toc.htm
In a nutshell you dont need downtime to maintain a standby, you can create them from a hot backup of your primary and get them recovering whilst it is open, in terms of which type of standby to use (physical or logical) that depends on your requirements for the use of the standby ... as I said read the doco (chapter 2 has a section on the benefits of each type).
HTH
Paul

Similar Messages

Configuring both logical and physical standby databases.

Hi,
I am trying to set up one primary and two standby databases which are physical and logical. together. What I am wondering is if i tis posiible to set both log_archive_dest_n parameters in init.ora of primary db to 'LGWR ASYNC'.. I tried to do that but I noticed that while redo data goes the first remote log destination including LGWR statement properly but for the second it does not.
So my assumption is only one remote archive dest. can be set for the LGWR process. Is ıt right?
Regards
ALPER ONEY
email:[email protected]

Hi,
when I set remote archive dest _n parameter for logical standby database to the value like 'LGWR AYSNC' and for the phy. standby to 'ARCH', it is ok. But if I change both parameters to 'LGWR'. I can see that only one destination receives the redo data and this destination is also the first destination configured for receiving redodata . I am just wondering that LGWR process is able to serve two or more to destinations at the same time. If it is ok, I am wrong and I better to try harder to solve the problem. I read the Dataguard document for 10GR' and the example for the case I created (two standby databases),, it uses ARCH process to send redo data and so everything is ok in that example.
P.S I also configured standbys for real time apply.
Waiting for your comments.
Regards.
ALPER ONEY

OEM for physical standby database

Hello All,
I am using Oracle 11.2.0.3. My enterprise manager is db console 11.2
I have Oracle Enterprise manager dbcnsole for my RAC primary database and I have created through sqlplus command line a physical standby database.
My questions
Can I use the RAC primary dbconsole to monitor my physical standby database? if yes what the steps?
Is it mandatory to use grid control in that case? if yes, what steps are needed to implement grid control ?
Regards,

Hi,
It is not possible to monitor/administer a Logical or Physical Standby database, i.e Data Guard, using Enterprise Manager Database Control. This is primarily due to the fact that Database Control is designed to monitor 1 database and a Data Guard environment, by definition, includes more than 1 database.
If you attempt to run emca against a standby Database, you will get an error like (i.e. ORA-01219: database not open).
Database Control, can, of course, be used to monitor the current Primary database (with no ability to administer or monitor Data Guard related functionality). In such a case, when failover occurs Database Control must be reconfigured to run on the new Primary database using the commands detailed in Note 278100.1 How To Drop, Create And Recreate DB Control In A 10g Database, section C. Recreate/ReConfig DB Control, Option 2. Recreate the DB Control Configuration Files and Repository.
Enterprise Manager Grid Control or Cloud Control provides the functionality for viewing, monitoring, and administering primary and standby databases in a Data Guard configuration.
Reference: Is it Possible to Configure Database Control for a Logical or Physical Standby Database? (Doc ID 315116.1)
Using EM cloud control 12c is best available option to monitor your standby databases
For install docs refer to
http://docs.oracle.com/cd/E24628_01/install.121/e22624/toc.htm
For Software download link
http://www.oracle.com/technetwork/oem/enterprise-manager/downloads/index.html
Regards,
Rahul

Logical and Physical Standby on same Node

Is it possible to have a logical and physical standby database for a primary database on the same node (i.e. primary on NodeA, logical and physical database of primary on NodeB)?
Will there be any conflicts with data guard broker with this configuration or any problems I may encounter?

From a technical point of view this is possible. Your standby node should be powerful enough to handle 2 instances. For even higher availability 3 dedicated nodes would be better. When Node B is down, both physical and logical standby are also down.
Werner

Creating a Physical Standby Database

Hi,
I'm reading Oracle® Data Guard
Concepts and Administration
10g Release 2 (10.2)
B14239-04.
In 3.2 Step-by-Step Instructions for Creating a Physical Standby Database chapter it says :
3.2.1 Create a Backup Copy of the Primary Database Datafiles and recommend RMAN to do that.
And in
3.2.4 Copy Files from the Primary System to the Standby System
Use an operating system copy utility to copy the following binary files from the
primary system to the standby system:
■ Backup datafiles created in Section 3.2.1
Finally

sorry , I did not finish.
I continue
finally,
3.2.6 Start the Physical Standby Database
Step 1 Start the physical standby database.
On the standby database, issue the following SQL statement to start and mount the
database:
SQL> STARTUP MOUNT;
I wonder , how to transform RMAN backup files to data files ? It is not explained or it is not necessary ?
Many thanks.

RE logical/physical standby database

1. Why logical standby database is SQL apply, and Physical standby database is redo apply? What ‘s the meaning/objective for that? (pls don’t tell me what is SQL/redo apply)
2. As we know, a logical standby database can be used for reporting and querying if primary database is down, why we still need a physical standby database (it can’t do that during recovering process, it just a same copy of primary database)? Why not just go ahead to set up only a perfect logical standby database? (just because logical one can’t accommodate all kinds of data type???)
3. Combined with Real time Apply and maximum protection, we can achieve a zero data loss, but could we achieve a zero downtime? Why or why not?

Go Through Below link
>>>Can you convert a Logical standby to a Physical Standby?

Logical standby database to physical standby database

I already start my logical standby database and I want to return it again to physical standby database. So what should I do?

>
The "may be" is because I have tested flashback of a physical standby to before resetlogs, but not a logical standby.
>
A physical standby keeps the DBID of the primary - a logical standby does not. That is exactly the problem that restricts the reconversion into physical from logical, and you did not encounter that problem.
>
I haven't used "keep identity" but from what I read it relates to "convert to physical" not "flashback database".
>
Exactly. And that is what the OP wants to do: convert to physical (from logical).
You mentioned that this might be possible with flashback.
Problem: During the conversion from physical to logical, the DBID gets changed unless you specify (in 11g) KEEP IDENTITY. This would make it possible to reconvert into phyiscal from logical.
In short: If there is no solution for the changed DBID of the logical standby in order to flashback it into physical as you suggested, then it is not possible .
When I saw your first answer, I thought that you might have a solution in mind in order to solve that obvious problem. Sorry for having bothered you.
Kind regards
Uwe
http://uhesse.wordpress.com

Physical Standby database Vs. Logical Standby database

I have few questions regarding capability of Logical Standby Database against Physical Standby database.
1. How efficient is Logical Standby database in terms of Physical Standby Database?? How both differ from each other and can I use Logical Standby Database for disaster Recovery?? Can It be use for recovering the failed Primary Instance?? If yes how efficient and reliable it is??
2. What are the known bugs and roadblocks for logical standby database on Oracle 10.2.0.1 on Soalris X86-64?
3.As logical standby database not going to replicate each and every schema of Primary database?? how is the change management effects to the logical standby from primary?? I mean there are some parameters and job that we create on primary how can it be transferred over to the logical standby??

1. How efficient is Logical Standby database in terms
of Physical Standby Database?? How both differ from
each other and can I use Logical Standby Database for
disaster Recovery?? Can It be use for recovering the
failed Primary Instance?? If yes how efficient and
reliable it is??I'm not sure what sort of "efficiency" you're talking about here...
Physical standby is just the old, tried and true application of archived logs to recover a database. Very solid, very old school.
Logical standby, on the other hand, is parsing the redo log, extracting logical change records, and applying them to the standby database. This obviously takes a bit more processing effort, it's newer technology, it doesn't have quite the level of support that physical standby does (i.e. certain data types are excluded), etc. You certainly can use it for failover, but it isn't quite as robust as a physical standby. Of course, this is getting better and better all the time and is definitely a focus of Oracle's development efforts.
On the other hand, logical standby systems can do things other than act as a warm standby. They can be open serving reports, for example. You can create additional structures (i.e. new materialized views) to support reporting. A physical standby is pretty much always going to be in managed recovery mode, so it cannot be queried.
2. What are the known bugs and roadblocks for logical
standby database on Oracle 10.2.0.1 on Soalris
X86-64?a) You'll want to do a Metalink search
b) If you're talking about a high-availability solution, why are you looking at a base release of the database? Why wouldn't you apply the latest patchset?
3.As logical standby database not going to replicate
each and every schema of Primary database?? how is
the change management effects to the logical standby
from primary?? I mean there are some parameters and
job that we create on primary how can it be
transferred over to the logical standby??I'm not sure I understand... Changes made to the primary generate redo. Oracle parses that redo, generates a LCR, and sends that to the standby database where that change record gets applied.
Justin

Will logical standby database be replaced by physical standby database?

Will logical standby database be deprecated or replaced by physical standby database because of Real Time Query?
As far as I know, because of the emergence of Real Time Query, physiacl standby database is easier to work than logical standby database. There are so many restrictions on using logical standby database.
Will logical standby database be deprecated in the future?
Message was edited by:
frank.qian

Good question - you are right that with the advent of Real Time Query, physical standby databases can provide the 'reporting database' functionality that you used to have to use a logical standby database for.
But remember that logical standby databases allow additional schema objects, like materialized views and indexes, that you can't have with a physical standby (for the reasons Hans mentions). For example, you could have a index-light primary database for OLTP style workload, and an index-heavy logical standby, with MVs and dimensions for reporting, DW, etc.
For this reason I don't expect logical standby will become deprecated.

Cannot Clear Critical Alert for Physical Standby Databases

10.2.0.4.0 Grid Control monitoring 10.2.0.4.0 databases and standby databases with 10.2.0.4.0 agents.
The standby databases are running on Xen guests. The O/S is Red Hat 4 Advanced Server.
I had a failure of Xen guest on Saturday that caused me to have to rebuild the standby servers. EM Grid Control successfully verifies the configurations and the status is normal for both physical standby databases. (A rebuilt logical standby database shows no alerts.)
Grid Control database targets page shows a single critical alert for each physical standby database. The alert is for "number of missing media files is 4". The metric graph shows the count as 0 since before the rebuilds. I cannot clear the alerts from the Critical Alerts page. Grid Control reports "The selected alert(s) cannot be manually cleared. They will clear automatically once the metric is no longer in a critical or warning state.".
Any suggestions?
Thanks,
Ray Westphal

Thanks for the reply Anthony.
The result of the query on both standby databases is '0'. The metric graph also shows the value at '0' since before rebuilds.
And the OMS db and agents have been reset several times since I posted this.
Ray Westphal.

How to convert logical standby database to Physical Standby Database

Hi,
Does anyone know how to convert logical standby database(10.2.0.3) to Physical Standby Database(10.2.0.3)? Is this possible? If so,please give me steps for it.
Thanks.
Regards,
RJ.

I don't believe this to be possible. One of the steps invloved in the creation of a logical standby is the following:
ALTER DATABASE OPEN RESETLOGS;
This makes the logical standby a different incarnation of the db from the primary.
A physical standby is a binary copy of a primary db, a logical standby is a completely seperate db that just happens to get sql statements applied to it that are generated from a primary db, but is open read/write.
One avenue, though would be if you had flashback database enabled and you flashed back all the way to when the db was a physical standby and then rolled forward with the archived redo logs.
It's somewhat unlikely you are in that situation, but that is a possibility.
Indeed the 11g snapshot standby does this sort of thing:
http://download.oracle.com/docs/cd/B28359_01/server.111/b28294/manage_ps.htm#sthref740
jason.
http://jarneil.wordpress.com

Can i convert logical standby database to physical standby database

Dear All,
Can i convert a logical standby database to physical standby database?
If yes, what are the steps to follow?
Thanks
Mahipal

I never needed or tested something like this, but below maybe usefull -
Transient Logical Standby
Users can convert a physical standby to a transient logical standby database to effect a rolling database upgrade, and then revert the standby to its original state as a physical standby database once the upgrade is complete - using the KEEP IDENTITY clause. This benefits physical standby users who wish to execute a rolling database upgrade without investing in redundant storage otherwise needed to create a logical standby database.
http://www.oracle.com/technology/deploy/availability/htdocs/DataGuardOverview.html
But opposite is documented - http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ls.htm#BEIGJCAC
best regards.

Physical standby database to Logical standby

Can I convert a physical standby database to Logical standby,

Go Through Below link
>>>Can you convert a Logical standby to a Physical Standby?

DB link for physical standby database

Hi All ,
I'm facing the below error on primary while trying to create a db link pointing to the 10g standby database which is in mount stage.
SQL> create database link synct connect to system identified by 123 using 'stdby';
Database link created.
SQL> select max(sequence#) from v$archived_log@synct where applied='YES';
select max(sequence#) from v$archived_log@synct where applied='YES'
ERROR at line 1:
ORA-02068: following severe error from SYNCT
ORA-01033: ORACLE initialization or shutdown in progress
Database version is 10.2 standard edition
My requirement is i need to get max(sequence#) of standby database from primary database using db link.
what i was trying to do is
on primary get max(sequence#) & get max(sequence#) of standby using db link and compare both if the gap differene is more than 10 send a mail.
Any suggestions will be really helpful

976422 wrote:
Hi All ,
I'm facing the below error on primary while trying to create a db link pointing to the 10g standby database which is in mount stage.
SQL> create database link synct connect to system identified by 123 using 'stdby';
Database link created.
SQL> select max(sequence#) from v$archived_log@synct where applied='YES';
select max(sequence#) from v$archived_log@synct where applied='YES'
ERROR at line 1:
ORA-02068: following severe error from SYNCT
ORA-01033: ORACLE initialization or shutdown in progress
Post Standby/DataGuard/ADG all questions further in Oracle Discussion Forums » High Availability » Data Guard
If you try to connect any users other than SYS in standby the error is very much expected. Of course you can connect with other users if you open database in OPEN READ ONLY mode, from 11gRx you can connect with other users even MRP is running if you are using ADG(active Data Guard licensed) .
I like to know, what you want to achieve by creating DB Link on physical standby database? Which is not allowed.
Database version is 10.2 standard edition
My requirement is i need to get max(sequence#) of standby database from primary database using db link.
what i was trying to do is
on primary get max(sequence#) & get max(sequence#) of standby using db link and compare both if the gap differene is more than 10 send a mail.
Any suggestions will be really helpfulNote:- Standard edition, Data Guard not enabled.
To use this you should use Oracle Net Service, you no need of DB Links.
Ex:- sqlplus sys/****@standby as sysdba
Here standby refers to Oracle net service, Where you will have entries in $ORACLE_HOME/network/admin/tnsnames.ora file.
Edited by: CKPT on Dec 12, 2012 2:01 PM

Issue on physical standby database

Hi
I've a problem on standby database.
I recently added a datafile on primary database, then I scp'ed the data file to physical standby database.On physical standby database I tried performing recovery.
I get following message in my alert log
WARNING! Recovering data file 88 from a fuzzy file. If not the current file
it might be an online backup taken without entering the begin backup command.
ORA-279 signalled during: ALTER DATABASE RECOVER standby database ...
how can I fix this now.
We keep physical standby database 2 day behind, and apply logs manually.
Physical standby database is maintained manually.
Could someone help me in getting out of this problem.
Oracle 9.2.0.7
solaris

Versus keeping it in manual mode, you can specify a time "delay" for the application of the logs:
From http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/log_apply.htm#i1022811
6.2.2 Specifying a Time Delay for the Application of Archived Redo Log Files
In some cases, you may want to create a time lag between the time when redo data is received from the primary site and when it is applied to the standby database. You can specify a time interval (in minutes) to protect against the application of corrupted or erroneous data to the standby database. When you set a DELAY interval, it does not delay the transport of the redo data to the standby database. Instead, the time lag you specify begins when the redo data is completely archived at the standby destination.
Note:
If you define a delay for a destination that has real-time apply enabled, the delay is ignored.
Specifying a Time Delay
You can set a time delay on primary and standby databases using the DELAY=minutes attribute of the LOG_ARCHIVE_DEST_n initialization parameter to delay applying archived redo log files to the standby database. By default, there is no time delay. If you specify the DELAY attribute without specifying a value, then the default delay interval is 30 minutes.
Canceling a Time Delay
You can cancel a specified delay interval as follows:
For physical standby databases, use the NODELAY keyword of the RECOVER MANAGED STANDBY DATABASE clause:
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE NODELAY;
For logical standby databases, specify the following SQL statement:
SQL> ALTER DATABASE START LOGICAL STANDBY APPLY NODELAY;
These commands result in log apply services immediately beginning to apply archived redo log files to the standby database, before the time interval expires. Also, see:
Section 12.8, "Using a Physical Standby Database with a Time Lag"
Oracle Database SQL Reference for the DELAY attribute of the ALTER DATABASE RECOVER MANAGED STANDBY DATABASE statement

Downtime for logical or physical standby database

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