Some RMAN Q's!
DBAsupport.com Forums - Powered by vBulletin
Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: Some RMAN Q's!

  1. #1
    Join Date
    Jul 2003
    Posts
    323

    Some RMAN Q's!

    SOME RMAN Q'S:-

    1. Backup of RMAN catalog: Using OS backup or another RMAN catalog?
    Read that if using OS Backup, BMR not possible in case of loss of catalog!
    2. Channels : Auto or Manual allocation - which is best - is it hardware/MML&MMS vendor dependent?
    3. Any BP's on Rman..links etc. ?

  2. #2
    Join Date
    Oct 2002
    Posts
    807
    1. Either way is fine. Most shops prefer OS or regular hot backups. What's BMR?
    2. A channel represents a stream of data to a device type. So yes, you gotta point this appropriately per the MML. Auto / Manual - your choice. Whatever works for you. Might as well set auto, and overide when required by manually allocating channels within your script.
    3. BP - Blood pressure? Here's a link to the RMAN user guide. It should address most of your RMAN questions.

    http://download-west.oracle.com/docs...a96566/toc.htm

  3. #3
    Join Date
    Jul 2003
    Posts
    323
    BMR->Block media recovery - for corrupt blocks!
    BP->Best practices( or anything learned by doin' it the hard way!)

  4. #4
    Join Date
    Mar 2002
    Location
    Mesa, Arizona
    Posts
    1,204
    Another option is to export, then push dmp to tape or remote disk.

    NUOA - Nice Use Of Acronyms
    "I do not fear computers. I fear the lack of them." Isaac Asimov
    Oracle Scirpts DBA's need

  5. #5
    Join Date
    Oct 2002
    Posts
    807
    Read that if using OS Backup, BMR not possible in case of loss of catalog!
    AFAIK, 'BMR' can be performed on the target with or without a catalog. So not sure what your concern is.

    BP - MBA speak (frequently used by gas bag PMOs). Strategize would be another one..or should I say 'strategery' instead!

  6. #6
    Join Date
    Jul 2003
    Posts
    323
    Hey Axr2,
    Are you sure? Kevin Loney's 9i DBA Handbook(for v.9.0.1.etc) - states what I posted that BMR not possible if catalog backed up by OS - unless fixed in later releases of RMAN(9.2+) !!


  7. #7
    Join Date
    Oct 2002
    Posts
    807
    AFAIK - "as far as i know". It indicates a certain level of uncertainity.

    Anyway - I've not performed RMAN BMR. But look at the below RMAN userguide and procedures for performing BMR. There is nothing there which explicitly or implicitly indicates that one absolutely requires a catalog. It's just a "blockrecover..datafile..restore" command. I don't see why this would *require* a catalog.

    http://download-west.oracle.com/docs...ov.htm#1008024

    (Pay attention to - Recovering data blocks with RMAN).

    I'd be interested in knowing why one needs the catalog for BMR, if you can lookup the information from the book.

  8. #8
    Join Date
    Jul 2003
    Posts
    323
    Nothing in the docs. - can only surmise that since it's in a format that only RMAN can read/write, an OS backup may not be of use.
    Have sent an e-mail to the author's website - will post if an enlightening reply is received!!

  9. #9
    Join Date
    Oct 2002
    Posts
    807
    Can you quote the lines from the book? Am guessing all that the author would've said is - you can't perform BMR on the target with an OS backup (of the target); but only with an RMAN backup (of the target). That is actually pretty obvious.

    And NOT
    BMR not possible in case of loss of catalog!
    like you said.

    All, I'm saying is you should be able to use the controlfile of the target to perform BMR even if you lose the catalog.

    OS/Traditional backups can't be used for BMR, because of the architecture (RMAN rereads fractured blocks without need for placing files in backup mode). For one, there is no interface with a traditional/OS backup to say "hey, I need block# to be replaced on file#", then read all my backed up archivelogs, look if this block has changed, and if it did - replace it (just that one corrupted block). RMAN has this capability because it tracks the information - it tracks used/changed blocks.

  10. #10
    Join Date
    Jul 2003
    Posts
    323
    Well the controlfile could be used unless the corrupt blocks info. is aged out & overwritten - do not remember if this is a permanent or circularly reused record in the controlfile - would expect it to be permanent - guess will have to pore deeper through the docs. - but will be obliged if you could clarify this. Will post the exact lines from the book when I can - the developer who brought this to my attention has it & have'nt been able to touch base with him yet !!


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  



Click Here to Expand Forum to Full Width