Bob,

   I think one of the first questions/items to examine is how many (and
what type) of interfaces are currently in use for the drives.  What type
of drives are they?  Do you have any performance measurement software to
let you know how the disk channels are currently being used?

   I went from a slow (HP-3000/950) system with 22 drives to a fast
(HP-3000/969KS-120) system with 8 drives.  My disk throughput has
increased due to the types of drives, and faster interfaces.  The
standard answer to your concern about an I/O bottleneck is "it depends".
You may notice an I/O performance improvement when you switch to
multiple volume sets since each will have it's own transaction manager.

   If you can provide more detail about your configuration, we might be
able to give some more specific answers.

                        Hope this helps,
                        David N. Lukenbill

--------------------------------------------------------------------
David N. Lukenbill
Hughes Missile Systems Company, Louisville
[log in to unmask]


   ----------
   From:       HP3000-L
   Sent:       Tuesday, September 23, 1997 11:22 AM
   To:         HP3000-L
   Cc:         bob.mueller
   Subject:    Protection from Disk Failure
   

        [snip]  I'm looking at ways to increase protection on my disk
   "Farm" in case
        of a disk-crash.[snip]
   
        My primary concern is losing user data that has been entered
   during
        the day, before the nightly back-up. We are a manufacturing
   facility,
        so although downtime is a concern, the loss of data is most
   critical.
   
        One given is to set up User Volume Sets (SYSTEM, PRODUCTION,
   TEST).
   
        I'm looking for some feedback from the list about any concerns
   or
        problems in using Mirrored Disk. With adding 4 more disk drives,
   I can
        set up the following configuration:
   
           System:         2 drives
           Production:     4 drives
           Prod Mirrored:  4 drives
           Test & other    4 drives
   
        My concern is the possibility of an I/O bottleneck by bringing
   the
        production data down to 4 drives, when it used to be spread over
   10.
   
        [snip]
   
   
        Bob Mueller                        [log in to unmask]
        M.I.S. Manager                     Phone: 201-967-3680
        Datascope Corp. - PM Division      Fax: 201-265-1867