Conference ulysse::rdb_vms_competition

67.0. "Distributed ADABAS" by HSK01::MANNISTO (Olli Mannisto, SWAS/SW Technology, Digital Finland) Fri Jan 15 1988 13:30

From:	HSK01::MANNISTO     "Olli Mannisto, SWAS/SW Technology, Digital Finland" 15-JAN-1988 13:40
To:	hsk01::mannisto
Subj:	adabas

    

              <<< KYOA::SYS$COMMON:[NOTES$LIBRARY]ADABAS.NOTE;4 >>>
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Note 15.2             Request for installed base experience               2 of 2
HSK01::MANNISTO "Olli Mannisto, SWAS/SW Technology," 32 lines  14-JAN-1988 12:19
                            -< distributed ADABAS >-
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    Originally I wrote this into the ADABAS notes, but obviously there's
    some details for this forum.... (They call this ADABAS 'add on' as
    ADARDA, Remote Database Access.)
    
    
    There's a way to run ADABAS in a cluster alike a 'distributed' ACMS.
    With ACMS you have the terminal activities (CP processes) on the
    front VAX's and the db on a VAX or VAX's. With ADABAS you can split
    the FMS+lang/NATURAL & ADABAS in two where the 'fronts' take care
    of terminal activities and run the applications programs while the
    nucleus (databas) stays within one VAX (cannot split a nucleus over
    several VAX's). The link front the front to the nucleus VAX is decnet
    and there's only one link per a front VAX es. front VAX processes share
    the same link to the nucleus. The nucleus can be where ever in the
    decnet and many nucleus's can share a VAX.
    
    The most striking thing with a 'distributed' ADABAS is that you
    need only a 'server' licence for the db machine (eg VAX 3600 with
    a server licence) and you can use relatively cheap VAX 2000's (or
    3500) as front machine's). And from system management point of view
    you can benefit running these VAX's as clustered.

    The decnet overhead in the case I've tested was 10% cpu time or less
    (10% as compared to application cpu usage). With ACMS you'll probably
    estimate the decnet cpu usage also as 10%. Using ethernet as a decnet
    link the difference between a one cpu solution and a front/back
    end was noticeable (close to measurement variations). The load balance
    between the front and the back end has been 40/60 - 50/50 depending
    on the applications.
    
    In our case the customers (two BIG) had a firm decision to use adabas.
    Otherwise I'd see that you'll have a happier future with dec products
    for several reasons.

    -- Olli