Conference ulysse::rdb_vms_competition

    Richard,
    
    I presume you mean that flavour of Rabbit that does disk
    de-fragmentation.
    
    Not from any personal bad experience, but I would steer clear of any
    disk defragmentation tools. If you look on one of the tuning notesfiles
    (VMSTUNING ?) you'll find a declaration by the file system engineers that
    they will not put any more time into trying to recover disks that have
    been badly mangled by such things. 
    
    Some questions to ask yourself and your customer :-
    
    o	What happens if the system crashes while the defragmenter is
        doing some of its more sensitive operations ?
    o	Does the defragmenter try and mess around with such files as
    	SWAPFILE, PAGEFILE, QUORUM etc (ouch) ?
    o	Why should a disk with an Rdb database on it become badly
    	fragmented in the first place ?
    o	Assuming sensible backup precautions, as well as RMU/BACKUP's
    	the occasional off-line full disk backup should be done. Just
    	restore that as part of normal operations to defrgament your
    	disk.
    o	Disk fragmentation is a symptom, defragmenting tools don't 
    	provide a cure, they just hide the symptom. What's really 
    	causing the problem ?
    Cheers.
    Tony J. (Who's  v e r y  nervous about these tools)
                            

I understand that there will be a Sales Update article soon saying that
you should stay away from de-fragmenters.

I hope that VMS does something in this area. Fragmentation is a problem,
backup/restore is not a great solution.

	  Recently, VMS Engineering has received many requests to
	  respond to the following questions:

		"When will DIGITAL recommend a third-party disk 
		 defragmentation product?"

		"Which third-party disk defragmentation product
		 will DIGITAL recommend?"

	  The following statement answers these questions:



          DIGITAL does not recommend the use of any third-party disk
          defragmentation product. DIGITAL cannot endorse any of them
          because strong circumstantial evidence suggests that some or
          all third-party products cause file, disk and system corruption.
          Because of DIGITAL's concern for the integrity of its customer's
          data, DIGITAL is not considering recommending any such product.

          Documentation on the VMS file system internals is not publicly
          available, therefore defragmentation utilities have been written
          without this information. The degree of knowledge one must have
          of the internals of the file system in order to write such a
          utility, coupled with the fact that the internals are undocu-
          mented and subject to change, leads DIGITAL to believe that only
          VMS Engineering can provide such a utility and guarantee its
          reliability.

          Therefore customers who choose to purchase and use a third-party
          defragmentation product must understand that DIGITAL, and more
          specifically VMS Engineering, cannot guarantee the integrity of
          the VMS file system and disk structure. Even if the utility is
          only run once, from that point forward the integrity of the data
          is at risk.

          VMS Engineering understands that disk defragmentation management
          is highly desirable, and a solution is on the VMS work list.
          However, because of current VMS Engineering commitments it is
          not possible to predict its availability.

          In the meantime, DIGITAL's advice for dealing with disk fragmen-
          tation is to backup and restore the disk. Planned performance
          enhancements to BACKUP will make this a more appealing recom-
          mendation.

          Once again, no third-party defragmentation package exists that
          DIGITAL has sufficient confidence in to recommend. DIGITAL
          rarely endorses third party products and then only when those
          products meet DIGITAL's standards. DIGITAL is not responsible
          for testing all third-party products or proving that they meet
          the standards of performance and quality expected of DIGITAL
          hardware and software products. Note that the use of a given
          product by one or more DIGITAL facilities is the choice of those
          DIGITAL facilities and does not constitute an endorsement of the
          product by DIGITAL.

    see also  ULYSSE::DOPTER    Rabbit known as DOPTER in Europe

    Tim

    
    From an ad' in the november issue of "Digital V�rlden", 
    a special magazine released by the swedish counterpart of
    Computer World,
    
    "..Digital has now evaluated and choosen RABBIT-7 for internal
    use all over the world. With a speed of 30-40 sites a week
    RABBIT-7 is now beeing installed on Digitals VAX-sites around
    the world. "
    [Digital V�rlden nr5 Oktober 1988]
    
    Anyone like to comment ?
    
    Stefan

A Digital MIS group is free to buy whatever outside products they like,
independent of what engineering feels, says, claims, or does.  They do
it all the time (witness 1032, FOCUS, POWERHOUSE, etc. use within the company).

If one of these internal MIS groups ends up corrupting a disk, the VMS
development team will no doubt tell them to go jump in a pool of acid
rather than offering to help rebuild the disk by hand.

In other words, what we do stupid (and at times unsupported) things
internally.  This does not mean that we should recommend that our
customers do the same.