RE: Table growth - disk sizing

For a home grown application or developed application where no real history exists it should be possible to estimate future growth based on expected transactions volumes if a few conditions are meant.  

1- Populate a clean test system with a realistic set of starting data using small physical space allocations
2- Run the system simulating a realistic workload distribution for a week
3- Compare the size of the system at the end of the week to the beginning size and divide the change in bytes by the number of transactions.  

You now have an average growth per transaction factor. But for it to be useful you must be able to reasonably estimate the number of future transactions and there cannot be much variation in the way the application is used by different sites.  

The problem is very few sites use realistic test data and almost no site is capable or willing to simulate a real production workload for a full week. Add to this the likelihood that the application either has a great deal of variation between sites or the transaction volume estimates are off by an order of magnitude and I would hazard a guess that only 5% of IT shops in the world can make accurate predictions.  

HTH -- Mark D Powell --

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Gogala, Mladen Sent: Friday, August 26, 2005 12:52 PM
To: 'Ranko Mosic'; Gogala, Mladen
Cc: Christian.Antognini_at_trivadis.com; tomday2_at_gmail.com; Oracle-L Subject: RE: Table growth - disk sizing

What I was trying to tell you is that the goal of your project can be qualified as BS. You are trying to predict the future based on number

of transactions, instead of the historical growth information, like everybody else. That will not work. Allow me to jovially suggest coin

toss, tea leaves, position of the stars or entrails of Oracle sales people
as the next best methods.
The only reliable extrapolation is linear approximation, based on historical
data. Even this gives you only short time reliability. Everything else is BS.

-- 
Mladen Gogala 
Ext. 121 

-----Original Message----- 
From: Ranko Mosic [mailto:ranko.mosic_at_gmail.com] 
Sent: Friday, August 26, 2005 11:18 AM 
To: MGogala_at_allegientsystems.com 
Cc: Christian.Antognini_at_trivadis.com; tomday2_at_gmail.com; Oracle-L 
Subject: Re: Table growth - disk sizing 

I was looking for useful advice, not bs. 
Thanks, rm. 


--
http://www.freelists.org/webpage/oracle-l