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Monday, December 29, 2014

Why Shall I be a DBA???

This post is mainly for the Freshers and for the beginners in the field of Database.....

Task of DBA is equivalent to the Events in life of an individual.

For the freshers, this is my first question. Why you want to be a DBA?

Well this has been asked to me several times, from my friends and from the interviewers...

Well for me, I just wanted a job, as I was fresher in IT field. Later when I was going thought the Oracle DBA Course, I understood what RDBMS is, and what's it importance. Well simply in a sentence I will explain it. "It's the record of Data, action or reaction you give while you are on the internet."  Let's take an example:
"Beginning from the world famous site GOOGLE, whatever you browse, search, everything is recorded in the GOOGLE database."

Well if you are bored enough reading this,,,,, Lets come to the point.

Database is the record of each and every transaction, and DBA is a person who holds the key to preserve this data. This data can be important to anyone, to GOOGLE or any other client.

But, to be a DBA, you need certain things, Lets keep these points in mind:

1. Be Focused, Just concentrate on the GOAL (This is an important thing which you must concentrate throughout you life )

2. Be Responsible (Take ownership of task, take everything seiously)

3. Time  (Give time, and try to reduce the time to resolve every problem)

4. Be Truthful (Never, never, never lie in your life, as you will be caught anyhow, if anyone wants to.)

5. Don't Panic (Take everything seriously, but don't panic, Decide what you wants to do, Make an Action Plan and estimate the time and ask for 1.5 times the decided time, so that if any problem comes in between, then you must be able to resolve it anyhow  ;)   )


That's all for today. Just keep this in mind.


-Next post will be the starting of the DBA course right from the beginning... and that will be free of cost. And that will be in sequence.


All your doubts and questions will be answered timely.

Thanks Folks,
-Venom  (That's What My Screen Name is)

Tuesday, December 16, 2014

Something about Rapid Cloning Part 1 - Database


During the interviews this is always asked, like "Tell me how do you do the Cloning in R12?"
We all know what happens in Cloning, but now we shall also know how is it done internally.
So I thought I shall dig up some information about how oracle works, whats the idea behind.
Starting with the few basic statements that we might have heard alot. I will put them in a question/answer pattern. 
In this post I am focusing only on the Database part. 


Q: Why do we need to do cloning?
-> To test some application by patching or coding which can affect the whole application or may need downtime for the process to be carried out. So, in order to avoid the loss in business due to these mentioned factors, we need to clone the Oracle Application.

Q. What are the different cloning methods supported by Oracle?
-> There can be many cloning methods but oracle supports only 1, i.e., RAPID CLONE.
      On the basis of Config.  We can divide them as
            1. With AUTOCONFIG. (Completely replaced by Rapid Clone now.)
            2. Without AUTOCONFIG. (
used before 11.5.5)

Q.  What is the need to run adpreclone?
-> This will create the staged clone directory which will be having the driver files and configuration file (XML File) of the source.

Q: How does adpreclone.pl dbTier will run

->   After runnning this, it will go in two stages
            1. dbTechStack                       2. Database

Q: Explain dbTechStack and Database in details:
-> It will create stage cloned area at $ORACLE_HOME/appsutil/clone This clone directory has got following main directories
data,jre,bin,db,html,context
This will prepare the database techstack at dbTechStack stage.
  1. Creates template files at $ORACLE_HOME/appsutil/template
  2. Creates driver files at $ORACLE_HOME/appsutil/driver/instconf.drv
  3. Converts inventory from binary to xml
Now the database stage:
      It will prepare database at the database stage. Major activities includes
  1. Create database control file script
      $ORACLE_HOME/appsutil/clone/context/data/stage/addbhomsrc.xml
      $ORACLE_HOME/appsutil/clone/context/data/stage/adcrdb.zip
       adcrdbclone.sql

  2. Generates database creation driver file
$ORACLE_HOME/appsutil/clone/context/data/driver/data.drv

  3. Copy JDBC Libraries
$ORACLE_HOME/appsutil/clone /clone/jlib/classes111.zip

________________________________________ 
NOW adcfgclone.pl dbTier (On TARGET NODE)

This will also run in two modes
     1. dbTechStack stage: 
It will make use template and driver files which were created during preclone process. And it will run the following scripts
      adchkutl.sh
      adclonectx.sh
      runInstallConfigDriver -
located in $ORACLE_HOME/appsutil/driver/instconf.drv
      Relinking of ORACLE_HOME/appsutil/install/adlnkoh.sh  
     2. Now for the Database Stage
            Driver File       $ORACLE_HOME/appsutil/clone/context/data/driver/data.drv
            Create Database using adcrdb.zip file
            Autoconfig is Run
            Controlfile is created using adcrdbclone.sql
     3. Generates database creation driver file
$ORACLE_HOME/appsutil/clone/context/data/driver/data.drv
     4. Copy JDBC Libraries
$ORACLE_HOME/appsutil/clone /clone/jlib/classes111.zip

Ok, Now you can sleep and dream about the cloning.
-----------  That's it ------