Conference cookie::archive_backup

    
    See note entry 361.4.
    
    
    Masami

    
    Masami...
    
    Thanks for your pointer - just the thing.
    
    
    Regards
    
    Chris D.
    
    

    
    Back again!!
    
    I advised the customer re: note 361.4 and he created a save request
    with 8 include objects using CREATE SAVE THDV69 FULL COM.
    
    He then used the PAB GUI to add another 10 objects to the save request.
    (The reason for this is that one of their systems has 18 disks).
    
    He started the save request. The 1st 17 objects backed up normally, but
    it failed on the 18th.
    
    (I have a full log file if anyone is interested)
    
    I advised the customer that this is probally due to a resource
    limitation, however he now is after a statement from DEC as to what is 
    the maximum number of objects per save request supported by PAB. 
    
    I advised him that if he wanted an official answer, then the answer is
    8.
    
    He was okay with this but now wants to know if their is some sort of
    work around to get the equivalent of two save requests to work together
    or be "piggy-backed" in some way. I said that I didn't think there was.
    
    Any replies, thoughts or solutions on the above would be greatly
    appreciated.
    
    
    Thanks in advance.
    
    Chris D.
    
    

    
    Please point to the log file.  We have never seen ABS thread fails with
    resource problem before.  Or, may be the operation failed due to some
    other reason, it may have nothing to do with resource constraint. 
    Please post the show/full output of storage class, execution
    environment and save request also.

    Could you tell us why this customer needs to put 18 objects in one request?
    For manageability reason, putting large number of objects like 18 is not
    a good thing to do.  ABS keeps track of "overall" result of save which
    is the maximum severity of all 18 objects.  So, if you have 17
    successful object saved, but the 18th one failed with fatal error for
    some reason, the entire save request is flagged as "fatal error".

    If you want to keep the tape drive busy, you do not have to put all
    objects in one request. ABS manages tapes/drives in a way that making
    separate requests can keep the drive constantly busy.

    Masami

    
    Masami, 
    
    Thanks for your reply again. The log files can be found in 
    
    		COMICS::DISK$DUMPS_B:[000000.DAVIDC_76413]
    
    As for why he wants 18 data objects in one save request, I'm not sure,
    but I think it has something to do with the way that the customer
    tracks his backups, rather than to keep the tape drive streaming.
    
    
    Many thanks
    
    Chris D.
    
    

    
    "Official limit of number of data object per ABS request"

    I discussed this topic within the engineering. The answer is we will
    officially support up to 8.  We did not document this clearly until
    now, but it will go into the next round of documentation. 

    The reason is that DCL limits to 8, and even if GUI can handle more
    objects, if there are more than 8 objects, the request cannot be
    handled from DCL interface.  We'd like to have ABS policy objects
    supported equally both from DCL and GUI. 

    	***************************

    If there is no strong reason rather than they want to execute the
    24 (or 18) requests "together", we'll strongly urge this customer
    to break apart their save requests into smaller requests.  By using
    the same storage class and execution environments, all data objects
    will be saved under same condition (using same drive, same volume
    set if you prefer).  

    Take 24 disks they have into some smaller logical groupings (or
    groupings in the order they want to backup). If you make 4 groups,
    there will be 6 objects each in a request. Schedule the request
    start time a little before the last save request is expected to
    end.  The next request will wait for resource (drive which is occupied
    by the previous request, and volume set being used) and as soon as
    the resources become available (when the previous request finished),
    the backup operation will start.

    24 disks can still be saved together in the same volume set with
    this layout, and you will also find it much more manageable to have
    smaller number of objects in one request.

	Masami

    
    Masami...
    
    Many thanks once again, I'll relay this to the customer.
    
    Much appreciated,
    
    Chris D.