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8 Replies Latest reply: Sep 8, 2013 12:48 AM by b0871b0f-8dba-4241-b823-384e41e9943d RSS

can any one explain me Rman retention policy and optimization on or off.

b0871b0f-8dba-4241-b823-384e41e9943d Newbie
Currently Being Moderated

1. what is meaning of retention policy redendency 1 or 2?

 

2 what is meaning of retention policy to recover window ??

 

3. what is meaning of optimization and what happens if  it is on and vice versa??

 

4. if optimization on  is it going to consider the read only & offline table spaces ??

 

5. if optimization off  is it going to consider the read only & offline table spaces ??

 

don't post any documentation  i have gone through the documents can anyone  plz let me know in simple or easy words  to understand to clear myself..  provide me  any real time examples

thanks for your valuable time and patience.   waiting for your replies...

 

 

thanks&regards

abishek

  • 1. Re: can any one explain me Rman retention policy and optimzer on or off.
    EdStevens Guru
    Currently Being Moderated

    b0871b0f-8dba-4241-b823-384e41e9943d wrote:

     

    1. what is meaning of retention policy redendency 2 ?

     

    Quoting directly from Database Backup and Recovery Reference"


     

    TO REDUNDANCY integerSpecifies that RMAN should retain integer full or level 0 backups of each data file and control file. The default retention policy setting is REDUNDANCY 1.

     

    What could be more clear than that?  What part of that are you having difficulty with?  In your case, as you read it, every time you see the word 'integer', substitute '2'.

     

    2 what is meaning of retention policy to recover window ??

     

    Quoting directly from Database Backup and Recovery Reference"


    TO RECOVERY WINDOW OF integer DAYS   - 

    Specifies a time window in which RMAN can recover the database.

    The window stretches from the current time (SYSDATE) to the point of recoverability, which is the earliest date to which you want to recover. The point of recoverability is SYSDATE - integer days earlier.

     

     

    What could be more clear than that?  What part of that are you having difficulty with?

     

     

    3. what is meaning of optimizer and what happens if  it is on and vice verssa??

     

    I assume you mean "optimization".  There is no "optimizer" configuration parameter for rman.

     

    Quoting directly from Database Backup and Recovery Reference"


     

    Optimization prevents RMAN from backing up a file to a device type if the identical file is already backed up on the device type. RMAN does not signal an error if backup optimization causes all files to be skipped during a backup. The backup retention policy affects which files backup optimization skips.

    For two files to be identical, their content must be exactly the same, as described in Table 2-3. When you create backup pieces on disk or on media managed by Oracle Secure Backup, optimization excludes undo data from the backup when the data does not belong to an active transaction.


     

    What could be more clear than that?  What part of that are you having difficulty with?

     


     

    4. if optimzer on  is it going to consider the readonly & offline tablespaces ??

     

    Are the files that implement those readonly and offline tablespaces identical to the previous backup of those files?  (See explanation for "optimization", above.

     

     

    5. f optimzer off  is it going to consider the readonly & offline tablespaces ??

     

    If optimization is off, what's to cosider?

     

     

     

    dont post any documentation  i have gone through the documents can anyone  plz let me know in simple or easy words  to understand to clear myself..  provide me  any real time examples 

    thanks for your valuable time and patience

    .

    Sorry, but the documentation is pretty clear on this.  I have gone against my own normal practice by quoting it instead of simply posting a link to it.

     

     

    iwill award with points .  waiting for your replies...

     

    Points?  Let's see, if I collect enough points, I get ... a different icon by my name.  Woo hoo!

     

     

    thanks&regards

    abishek

  • 2. Re: can any one explain me Rman retention policy and optimzer on or off.
    Aman.... Oracle ACE
    Currently Being Moderated

    1. what is meaning of retention policy redendency 2 ?

    The most recent two copies would be kept and the previous ones would be marked as obsolete. Try it out using RMAN.

     

    2 what is meaning of retention policy to recover window ??

    Instead of number of copies, the concept of making the backups obsolete shifts to number of days. Try it out using RMAN.

     

    3. what is meaning of optimizer and what happens if  it is on and vice verssa??

    Meaning of optimizer is to "optimize" the query execution. It's always on which means the queries are always optimized.

     

    if optimzer on  is it going to consider the readonly & offline tablespaces ??

    Hmm do you even understand what are tablespaces all about?

     

    optimzer off  is it going to consider the readonly & offline tablespaces ??

     

    Ditto answer given above for this as well.

     

    dont post any documentation  i have gone through the documents can anyone  plz let me know in simple or easy words  to understand to clear myself..  provide me  any real time examples

    Well, first thing is that you can't decide for the volunteers that whether they should or shouldn't post documentation. Second, you haven't gone through the documentation. If you have read, you probably have just read a very tiny bit of it. If a person asks that using optimizer, whether the read only or offline tablespaces would be considered or not, he needs to really get back to the documentation and first understand the basics of the oracle database along with going to a classroom training. You are lacking , big time, in the understanding of the database concepts.

     

    thanks for your valuable time and patience. iwill award with points .  waiting for your replies...

    Well, guess what, it won't matter that you would award points or not. Most, who answer questions here , do it because they love to help others and that has nothing to do with the points.

     

    Aman....

  • 3. Re: can any one explain me Rman retention policy and optimzer on or off.
    b0871b0f-8dba-4241-b823-384e41e9943d Newbie
    Currently Being Moderated

    hi edstevens,

     

    thanks for your reply.  i m sorry for the mistakes..

     

    im new to this, . im not good at documents or technical language. so ace explained me in easy manner that is what  i want.

     

     

    apologies if my question wrong..

     

    1  i register target database and optimization is on. took RMAN full backup yesterday.

    today morning i have made some changes in one table space ( inserted some records in to one table belongs this table space) and i put it offline or read only.. 

    next step is i keep optimization on. i will take the backup  is it consider that table space modified blocks. or not.

     

     

    2. i register target database and  optimization is on. took RMAN full backup yesterday..  .  

        today morning i have made some changes in one table-space ( inserted some records in to one table belongs this table space)  and i put it offline or read only.

        i keep optimization off. so what happen in this case.

     

    this time i wont mention about points because i understand .    

     

    thanks& regards

    abishek.

     


     

  • 4. Re: can any one explain me Rman retention policy and optimzer on or off.
    b0871b0f-8dba-4241-b823-384e41e9943d Newbie
    Currently Being Moderated

    hi aman,

     

    Thanks for your reply.. you have explained me in easy manner.

     

     

    Well, first thing is that you can't decide for the volunteers that whether they should or shouldn't post documentation. Second, you haven't gone through the documentation. If you have read, you probably have just read a very tiny bit of it. If a person asks that using optimizer, whether the read only or offline tablespaces would be considered or not, he needs to really get back to the documentation and first understand the basics of the oracle database along with going to a classroom training. You are lacking , big time, in the understanding of the database concepts.


    a. i mention that point about documentation.. cause repeating the same thing is time waste for all  and me too. so that's why highlighted there.. .


    b.  im sorry for wrong question . i have modified it..


    i guess may this question right ..


    1  i register target database and optimization is on. took RMAN full backup yesterday.

    today morning i have made some changes in one table space ( inserted some records in to one table belongs this table space) and i put it offline or read only..

    next step is i keep optimization on. i will take the backup  is it consider that table space modified blocks. or not.

     

     

    2. i register target database  and  optimization is on. took RMAN full backup yesterday..  . 

        today morning i have made some changes in one table-space ( inserted some records in to one table belongs this table space)  and i put it offline or read only.

        i keep optimization off. so what happen in this case.



    Well, guess what, it won't matter that you would award points or not. Most, who answer questions here , do it because they love to help others and that has nothing to do with the points.


    i mention this casually. some body love to help. some of them help for points. some may be  sharing knowledge. anything it depends on the person.  i don't think  no need to highlight that point..


    thanks&regards

    abishek.


  • 5. Re: can any one explain me Rman retention policy and optimization on or off.
    Pradeepcmst Journeyer
    Currently Being Moderated

    Hi Abhishek,

     

     

     

    1) If you set retention policy to redundancy 2, RMAN will keep only last two backup copies and it will mark the rest of the backup copies as obsolete(which means no need for recovery)

     

    2) If you set retention policy to recover window to 5 days, no matter how many backups you take, RMAN will keep the last 5 days backup. And the backups before last 5 days will be marked as obsolete. So both retention policy are different which serves different purpose. We can use according to our requirement.

     

    3) Optimization means determining the most efficient way to execute the statements. When you turn on backup optimization, all backup commands will skip backups of any file if it has not changed and if it has already been backed up to the allocated device type.  A file can be any dbf file, an archived redo log or an RMAN "backup set". If you turn off backup optimization, all files are backup up no matter it has been already taken.

     

    4) If backup optimization is configured, RMAN skips backups of offline and read-only datafiles only if the most recent backups were made on or after the earliest point in the recovery window

     

    5) If backup optimization is not configured, RMAN will take all backups including read only and offline tablespaces.

     

     

     

     

     

    Hope this helps!!

     

     

     

     

    Regards,

    Pradeep. V

  • 6. Re: can any one explain me Rman retention policy and optimzer on or off.
    EdStevens Guru
    Currently Being Moderated

    b0871b0f-8dba-4241-b823-384e41e9943d wrote:

     

    hi edstevens,

     

    thanks for your reply.  i m sorry for the mistakes..

     

    im new to this, . im not good at documents or technical language. so ace explained me in easy manner that is what  i want.

     

    I don't want to be harsh, but you are working in a technical field whose practitioners (even "aces" and "gurus")  are highly dependent on documentation. 

     

     

     

    apologies if my question wrong..

     

    1  i register target database and optimization is on. took RMAN full backup yesterday.

    today morning i have made some changes in one table space ( inserted some records in to one table belongs this table space) and i put it offline or read only..

    next step is i keep optimization on. i will take the backup  is it consider that table space modified blocks. or not.

     

     

    2. i register target database and  optimization is on. took RMAN full backup yesterday..  .  

        today morning i have made some changes in one table-space ( inserted some records in to one table belongs this table space)  and i put it offline or read only.

        i keep optimization off. so what happen in this case.

     

    I could explain it.  Someone desperate for points probably will.  But you would be better served in your career if you set up a test and see for yourself how it behaves. Before the test, write down what you expect and why.   And if it doesn't behave as you expect, see if you can explain the reason to yourself then post the results of the test and your explanation for review. 

     

     

    this time i wont mention about points because i understand .

     

    thanks& regards

    abishek.


     

  • 7. Re: can any one explain me Rman retention policy and optimzer on or off.
    b0871b0f-8dba-4241-b823-384e41e9943d Newbie
    Currently Being Moderated

    hi edstevens,

     

    i apologies for late reply.

        thanks for the suggestion  i will follow what you have said to me..  i understand the concept now. i got clarity.



    thanks&regards

    abishek.

  • 8. Re: can any one explain me Rman retention policy and optimization on or off.
    b0871b0f-8dba-4241-b823-384e41e9943d Newbie
    Currently Being Moderated

    hi pradeep,

     

    sorry for late reply.  it is very  helpful for me to understand  the concept. once again thanks for your reply..

     

     

    thanks&regards

    abishek.

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