Significance of incrementally updated backups?
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Thread: Significance of incrementally updated backups?

  1. #1
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    Thumbs up Significance of incrementally updated backups?

    Can any one let me know the significance of incrementally updated backups?

    I understand that in incrementally updated backups we apply all the incremental backups to level 0 backup and update it.


    But what is the real use of it?When we can always take a level 0 or full database backup...Please shre your views.


    Regards,
    Mohith.

  2. #2
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    so when you do a restore it takes less time

  3. #3
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    you mean to say that restoring from incrementally updated backup will be quicker than updating from full backup.....How is it possible?

  4. #4
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    ok, misread your first question.

    Some people dont have enough take to take a full backup every night, or dont have the space to keep fulls every night.

    Thats why you do incrementals

  5. #5
    You can restore an incrementally updated backup by doing a 'switch datafile', after which oracle just attaches to the datafile and uses it. Must faster then doing a cp of the file back into the original location.

  6. #6
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    It has to mainly do with the time savings and disk space savings, as both of these are lesser with incremental backup.

    We can't imagine taking a daily full hot backup for a database of size say 500G or 1TB etc...Depending on the hardware configuration, it can take good amount of time and more importantly has an impact on end-user performance and hardware resource consumption. What is the use of taking the backup of whole database, if it has not changed completely ?

  7. #7
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    @@ simple dba

    Even i know the significance of incremental backups mr.But i request you to
    go through Oracle Documentation and read about Incrementally updated backups and then answer to this post [].This is one of the silliest things people often confuse/not aware of difference between incremental backups and incrementally updated backups.....so mr.simple dba please got hru document and then put a smiley ok....[]

  8. #8
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    As I understood, the incrementally updated backups primarily help when you have to restore or recover the database.

    Before going down this route, it might be good to compare the time savings on your environment for a level 0 vs. level 1 backup. Based on that, you could decide whether a level 1 with incrementally updated option is better or level 0 is better.

    There is certainly advantage for incrementally updated backups. As an example, if I take level 0 backup on Sunday and take level 1 from Mon-Fri. On Sat, if recovery needs to be done, it would involve restoring level 0 of Sunday and applying the 5 incrementals taken during the week.

    With the incrementally updated backups, I would have to apply only 1 incremental, since my level 0 backup of Sunday is already recovered and pushed forward to Thursday (with incrementally updated backup feature) and I only need to apply Friday's incremental.

    Instead of spending the time during actual recovery, the time is spent during a normal backup.

    I found the below article to be useful in understanding this feature
    http://www.nyoug.org/Presentations/SIG/DBA/10grman.pdf (i like to end my responses with a smile..didn't mean to offend)

  9. #9
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    thanks for the link it was useful....i think i was bit harsh in the previous post....sorry for that...[]

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