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Conference cookie::archive_backup

Title:Archive/Backup
Moderator:COOKIE::MHUAIG
Created:Wed Sep 08 1993
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:479
Total number of notes:2283

421.0. "Complex schduling - how it works" by COOKIE::MHUA () Thu Apr 10 1997 09:57

    How ABS's complex scheduling works

    The engineering had misunderstandings about how this was supposed to
    work until recent inquiries from customers. This is to clarify how 
    it's supoosed to work, so that we know when something "unexpected"
    happens, then it's a problem to be reported.

    ABS provides several types of complex schedules.  We will take "weekly full
    with daily incremental" (referred as WFDI schedule) as an example here. 

    In WFDI schedule and other comples schedule full-Incremental schedule 
    happens on a fixed date.  It means that if the first full is kicked off 
    on Monday, it will always do FULL on Monday even if some incremental
    levels are skipped.

    So, in essence, WFDI schedule will run like this on a fixed schedule:

    Example A:

    Monday    FULL
    Tuesday   Level 1
    Wednesday Level 2
    Thursday  Level 3
    Friday    Level 4
    Saturday  Level 5  
    Sunday    Level 6
    Monday    FULL

    We have a customer setting up DECscheduler special days to skips Saturday 
    and Sunday opetrations.  In that case, Level 5 and 6 are not 
    performed and it resumes with FULL on Monday.

    Now, in case of failure in any of these schedules, here's what should
    happen.    ABS considers success and qualified success (most of backup
    warnings) as success.  All other status is considered failure.

    If the full operation is a failure, instead of incremental, ABS retries
    FULL until we have a success in FULL operation.  Let me describe in an
    example.

    Example B:

    Date       Time run          type   result
    Monday    31-Mar-1997 02:00  FULL - failure
    Tuesday   1-apr-1997 02:00   FULL - failure
    Wednesday 2-apr-1997 02:00   FULL - success
    Thursday  3-apr-1997 02:00   Level 3 - success
    Friday    4-apr-1997 02:00   Level 4 - failure
    Saturday  5-apr-1997 02:00   Level 5 - success
    Sunday    6-apr-1997 02:00   (Assume skipping this day using scheduler
                                  tricks)
    Monday    7-apr-1997 02:00   FULL - success

    Notice that the FULL operation is repeated until it finally succeeds on
    Wednesday.

    If the one of the incremental level fails, it simply skips the failed
    level and goes to the next level.  It does not repeat the same level.
    In the above example, Level 4 fails on Friday, but on the next say,
    it does Level 5. However, it does not skip in terms
    of the contents of the incremental backup.

    In the example B, Level 5 backup on Saturday will backup all new/modified
    files since that last successful either FULL or lower level incremental
    backup.  The backup command on the save log on April 5th will say,
    
    $backup/...(lots of qualifiers here.../since="3-apr-1997 02:00:00.00"

    The last successful lower level incremental backup was on April 3rd,
    and all changes since the specified date/time in the command are in
    this save operation.

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421.1CX3PST::BSS::SAULThu Apr 10 1997 13:293
This is helpful.  Can we put this out for customer consumption?  Thanks.

Ted
421.2Maybe STARS article?NABSCO::HELLWIGFri Apr 11 1997 09:097
Please do.  I believe it will be helpful for customers to understand
this.  It will also be described in the documentation.

Kim


421.3Inquiries on ABS's internal backup scheduleHLSM01::HENK_HHenk Hofman @UTOTue Apr 15 1997 03:2624
Re .0

Some practical questions.

- Can you get from ABS an overview, in one go or one save at a time, what
  settings ABS is using for the full backups. In your example the FULL will
  run on monday but is there a way to tell from the 'outside'.

- Is there a way to change the full-setting for a specific save request ?

  Full backups often run sometime in the weekend and testing a full is
  not what I have in mind as nicest thing to do for the weekend.

  (Other then creating two identical save requests, one for testing
   purposes and another as 'the real thing').

- In your example the full backup runs on monday but day-to-day operations
  may require this weeks full on tuesday how do you accomplish this ?

  I know how to use special days in the scheduler but restore-time and
  or media-movement requirements can imply that skipping this weeks full
  is not an option.

Henk.
421.4How to move the FULL-Save day now ?ATZIS1::PIEBERchaos has many facesFri Apr 18 1997 10:5921
    Hi,
    
    can somebody shed some light on this ? I have been told, that WFDI is a
    'set-and-forget' type schedule. However, if I need to move the FULL
    save from the original day (as is the case at a production site here)
    to different day, I can see only one way to accomplish this:
    
    � delete the SR and start over.
    
    However, this certainly has a price:
    
    � I have to use ABS DELETE SAVE/OVER to get it done at all.
    � create a new SR with the same characteristics, but now a different
      start date.
    � What about the restore ? Having a reference count greater than zero
      obviously means, that the structure I am removing is still of value 
      to another structure (UID in catalog ?).
    
      Can I restore data backed up before the delete of SR at all ?
    
    Ewald.
421.5re: .-1COOKIE::MHUAFri Apr 18 1997 15:4615
    
    Ewald,
    
    Your solution of how to get around to rest the FULL save schedule
    is correct.
    
    About restoring the files after deleting the originating restore
    request, this should not be a problem, as long as the catalog and
    the tape media are kept.
    
    Let me think about if I can come up with a easier a way to reet 
    the FULL date.
    For now, your method is correct.
    
    Masami
421.6Here's the wayCOOKIE::MHUAFri Apr 18 1997 17:1722
    
    Ewald,
    
    I figured out the way to reset the FULL schedule from GUI. Here's
    how you do it.
    
    1. On GUI, get into SET SAVE screen and chose "scheduling and retention
    option".
    
    2. On schedule interval field, pull the option down and rest the
    option to "daily incremental with Full weekly" - although it's 
    the same option used, this will cause a field in internal ABS to reset.
    
    3. Make sure to change the start time field to the date/time you want
    the operation to restart.
    
    4. Click enough OK buttons to get out of GUI.
    
    After this, the next operation will be FULL again.
    
    Masami
    
421.7I'll check it...ATZIS3::PIEBERchaos has many facesMon Apr 21 1997 09:298
    Hi Masami,
    
    thanks for the input. If this really works to shift the full day,
    *PLEASE* make sure, it gets included into the docs.
    
    I ask the customer to check this and come back with the results.
    
    Ewald.
421.8How to tell on what day the Full will run...HLSM01::HENK_HHenk Hofman @UTOTue Apr 22 1997 03:408
Re .6

Thanks for this solution, it answers question-2 and -3 from 421.3.

Remaining question from 421.3 is how to tell from the outside on what day
ABS will run the Full Backup.

Henk.
421.9COOKIE::MHUATue Apr 22 1997 09:487
    
    The only reference material we have to see which day what schedule
    (full or what level of incremental) is appendix D of ABS doc. The day 1
    of schedule is FULL, based on that, you should be able to tell
    which level should run on a particular day.
                                
    Masami
421.10Consider this a requirement for a future version?BIGUN::KEOGHI choose to enter this note now.Thu May 01 1997 02:1014
Masami,

I would consider this a request for functionality in a future version.
Several other scheduling products provide a capability to answer "what if"
questions such as this. Have a look at CA UNICENTER Workload scheduling
for example.

Questions such as "what backups will run tonight?" or "when will this full
backup run?" are frequently asked in support of scheduling other events
(downtime etc.), so it would be good if ABS had a method of answering these
questions.

Regards,
Patrick
421.11COOKIE::MHUAThu May 01 1997 09:5812
    
    Hi,
    
    Will you summerize the requirements and send it to
    COOKIE::CROSS (Judy Cross).   I will point to her that this note entry
    contains a future requirement.  However, to make sure your request 
    is correctly reflected in our requirements list, we prefer for you
    to write down a paragraph or two about how you want this feature to
    work and send it to Judy.
    
    Thank you,
    Masami