Re: Delete Records -File Re-org

Yes, and what about the cost of downtime?  Perhaps you can use the following 
equation:
R=Run rate of the application.  Or estimate of cost of downtime in Currency/Hour
D=Length of downtime
S=Cost of AS/400 storage.  Which in my experience is $0.60/meg
R$/Hour  *  D Hours  *  meg/$0.60  =  meg
So if your cost of downtime is $400/hour, and it took 3 hours to reorg your 
files, then you had better saved 2,000 meg or 2gig of dasd.  Otherwise your 
wasting your companies money that would have better spent buying DASD.  
Unless you dramatically increase response time.  And yes, there are formula's 
for response time.  IBM published a document years ago on the value of response 
time.  Batch is easy.  If it makes a job that ties stuff up faster, than use 
your run rate.  For example, if a batch job now finishes in 15 minutes versus 
30 minutes, and your run rate is $400/hour that you've saved the company $100 
in processing time.  BUT, if it takes 3 hours to reorg, and you only saved 
500meg of dasd and you only run this batch job once in a blue moon, then 
you've cost the company:
(3hours  *  $400/hour)  -  ($100 batch job)  -  (500 meg * $0.60/meg) 
= $1,200  -  $100  -  $300  
=  $800 of lost money





dgallagher@deloitte.ca on 02/18/2000 10:00:20 PM
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Subject:        Re: Delete Records -File Re-org

Phil:

As others on this list have said . . .there is absolutely, positively, no
question that you will save disk space by re-org'ing to get rid of deleted
records in files. You may have to find a way to break it gently to your
co-worker (or boss).

I will send you privately an article I wrote for TUG/400 magazine. It
outlines how to create a report that shows how much disk space is being used
by deleted records. At my previous employer, I ran this report every week to
see which files we should re-org at the next window in the data centre
schedule.

Due to application design (as Al Barsa mentioned), we were unable to change
all files to re-use deleted records. If my own experience with JDE support
is any indication, you will never get enough info from them to determine if
it is safe to change your files or not - so assume you can't. We also had
users in many time zones, so the window for doing re-org was usually small -
couldn't run them all or even a whole library every weekend.

As others mentioned, it will be difficult to know how long the re-org will
run the first time you do it - Pete outlined some of the factors. We used to
keep track in the data centre to help with planning. Once the re-org starts
to run, no one can use the file until the re-org is finished.

You will be able to prove to your co-worker (or boss) how much disk is
saved. Run the deleted records report before and after a re-org. The file
size and number of deleted records will be on the report.

Debbie Gallagher
dgallagher@deloitte.ca

------------------
Original message
------------------
From: pike4@ix.netcom.com 
Subject: Delete Records -File Re-org
>
>   <snip>   re-orgs on these files during the week end, and was told that
this doesn't 'really' save
space. <snip>
>Thanks,
>Phil Kestenbaum
>
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