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When you say create standby database is it synonymous to DATAGUARD? or the manual standby? or the poor man's standby?In oracle standby database, redo log is applied to the standby database to keep it in sync with the primary database.
Dataguard is a setup where one or multiple standby databases are configured which are in sync with primary database all the time and all this is done by Oracle itself.
What this guy is doing here is creating a copy of primary database and having manual methods to extract redo logs from primary and then shifting them to standby using his own written scripts. Doing this also needs a license from Oracle and hence this is not a "poor man's standby". Because Standard Edition does not have capability of data guard, hence this guy is using his "own" method of standby database. Remember, this still needs a separate standard edition license to have this kind of standby.
Can this poor man's standby be able to switch over the standby to primary? and back again from primary to standby?NO. In case of primary database failure, you can't execute any dataguard standard command to failover (switchover will also not work here). You need to manually recover this "manual" standby and then open it using resetlogs and then direct your applications to this database.
Manually remove standby databse
What did Tom from the link above has setup? is it a dataguard or just manual?This is data guard configuration.
Edited by: Salman Qureshi on Apr 18, 2013 2:42 PM
I thank you all :)
What did Tom from the link above has setup? is it a dataguard or just manual?This is not data guard, you may call it a manual standby database (also not supported by Oracle)
Can Tom setup be able to switch from standby to primary as well?
It is not clear to me :(
How many types of standby database does oracle have or how many variations or how many flavors?
When I run the command "create standby database" .....is it creating a DATAGUARD, or other types? or does all "standby database" always used this command?
Why is that in 11gR2 RAC cluster is already included or free. Does it include free standby license too?
Edited by: yxes2013 on 17.4.2013 22:49
Data guard is a term and Physical Standby is a type of the standby database within a dataguard configuration i.e. dataguard is just the new marketing label for standby, resulting from an extra interface (Dataguard manager or Dataguard broker) to manage the standby database.
Two types of Standby Database (a) : Physical Standby Database (b) Logical Standby Database
How they creates and how they works, read relevant version's Oracle docs.
Edited by: Girish Sharma on Apr 18, 2013 11:19 AM
Aman And Sybrand @ Difference between physical standby database and Data Guard
Which of the above is capable of swithing over from standby>primary>standby? I guess no.2?You can switch over to / from both type of Standby Databases.
Switchover of Physical standby database in 11g
[url http://books.google.co.in/books?id=cpkWoXEWlTsC&pg=PA542&lpg=PA542&dq=switch+from+primary+to+logical+standby&source=bl&ots=WevVPmkVpc&sig=rHowpC9tS50lIG2ULL5mlPajSwY&hl=en&sa=X&ei=XYxvUf3fNISzrAfc4IDwAQ&ved=0CGcQ6AEwCQ#v=onepage&q=switch%20from%20primary%20to%20logical%20standby&f=false]Switchover to Logical Standby database
You can actually build combinations -- e.g. a "scripted and automated" "standby" not using a standby controlfile, a "manual" standby using a standby controlfile etc.
Oracle allows flexibility in how you setup standbys.
However, in general, using the Enterprise Edition, you build a standby with a standby controlfile and dataguard.
Using Standard Edition, you build a "manual" or "scripted" standby because dataguard is not available in Standard Edition.
Hemant K Chitale