RE: Journaling performance

[Buck Calabro <buck.calabro@xxxxxxxxxxxxxxxxx>]

John Earl wrote:

>Does anyone know of a benchmark 
>for journaling on the AS/400?

Alas, no.

>I'm involved in a discussion with 
>someone who refuses to believe
>that journaling will not bring a 
>system to it's knees.   I could
>create a test, but it would be 
>better if this information came
>from some independent third party.

I just went through this.  We have a customer who REQUIRES commitment
control and I had a devil of a time trying to convince all involved that:
a) journaling is NOT a performance hog
b) journaling will NOT cause random CPFxxxx messages
c) journaling will NOT cause other apps that use these files to break

In the end, I followed the sage advice of Mark Twain.  "It is better to ask
forgiveness than permission."  I wrote a CL program that turns journaling on
and off (avoids the manual typing thing) and turned journaling on over some
30 files.  In the test/conversion environment at first.  Results:

a) nobody noticed journaling was on
b) nobody noticed journaling was on
c) nobody noticed journaling was on.

It's been over a month and none of the programmers, system administrators
(backups, etc.) or users has been in the least bit affected by the fact that
journaling was turned on continuously.  We've run 20+ conversions from the
old system to the new one, each adding some 500k records to the journaled
files.

This weekend we did the live conversion.  Journaling was turned on in the
production system before they started and it worked just as it did in the
test environment.  Anecdotal?  Perhaps.  But I've never, EVER understood why
AS/400 people have had such a fear of journaling.  Even when it was new on
the S/38 and had problems, they were PTF'd quickly enough.  

Buck Calabro
Aptis; Albany, NY
"We are what we repeatedly do.
 Excellence, then, is not an act, but a habit." --Aristotle


Billing Concepts Corp., a NASDAQ Listed Company, Symbol: BILL
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