Re: DB sizing - whitepaper

Ramesh,

I still don't know exactly what you mean by 'database sizing'.  If what you really mean is 'disk capacity', the most important factor today is the number of I/O's available on your most active tablespaces and the redo log files.  Frequently, you end up with a situation, that your disk capacity measured in GB is easily fulfulled using just a few physical drives, but your I/O requirements cannot be fulfilled with such a setup.  Disks of 50 or even 100 Gb, which are getting common these days are simply too big as you end up with too few of them, but it can be really hard to argue with your purchising division that you need 1Tb of disk if you are only storing 100Gb.  So you need to argue that you need 500 I/O's per second and lie about the number of GBs you get.

And again - you are back to the application, and the only real way to get to a number of necessary I/O's is testing.  If your application is very well written, you should have good chance of extrapolating from a small test setup to a large production environment, but unfortunately, applications are not always well written...

Thanks, Bjørn.

rpapnoi_at_chemtex.co.in wrote:

  BjørnWhat you say is true. Now my question is What should be the answer to the question "How you plan the Database sizing for a given application?". I faced it in a DBA interview. I did mention about the requied tablespaces, storage parameters etc depending on Application size. Am I missing something? Seniors, please advice.Regards,Ramesh D PapnoiOracle DBA @ Chemtex Global Engineers Pvt. Ltd., Mumbai, India(BrainBench & Brainbuzz Certified Oracle 8/8i DBA & Developer)http://www22.Brinkster.com/rpapnoi---------- Original Text ----------To: internet["Multiple recipients of list ORACLE-L" <ORACLE-L@fatcity.com>]Ramesh,I presume you are looking for something to tell you how to configure a database server, and such a thing does not exist. Period.The real answer is, that this is far too application dependent, and that only the application developers can provide anything of this kind. And even in this case, such configuration guides are often more misleading than guiding. There have been attempts at making rules like "this application is like X tpc-c transactions", but they also fail to be of any actual value.Also, if what you really were looking for was something to tell you the size (in GB) of the required disk to store schema with a certain definition, you could create some rough estimates. However, with todays typical disksizes, you run out of spindles much before you run out of GB.Thanks, Bjørn.rpapnoi_at_chemtex.co.in wrote:   

    Hi Gurus,Can anybody mail me the the whitepaper/policy document on database sizing? Thanks in advance.Regards,Ramesh D PapnoiOracle DBA @ Chemtex Global Engineers Pvt. Ltd., Mumbai, India(BrainBench & Brainbuzz Certified Oracle 8/8i DBA & Developer)http://www22.Brinkster.com/rpapnoi                               Received on Thu Feb 14 2002 - 09:36:54 CST