Oracle-L: Re: Choose a datafiles size

From: Bruce Pihlamae <bpihlama_at_NLA.GOV.AU>
Date: Mon, 22 Jan 1996 08:51:07 +0000
Message-Id: <9601212214.AA25924@alice.jcc.com>

> Hello,
>
> I would like to know if it's better to create for a tablespace, one
> datafile of 100Mb, 2 datafiles of 50Mb or 5 datafiles of 20Mb.
>
> I would like to know if the big (>100Mb) datafiles are better than the
> small datafiles (<100Mb).

There are five reasons why you would use multiple datafiles to construct a single tablespace.

Your tablespace is larger than your disk size so you have to use multiple datafiles to spread it across the disks.
You want to spread the I/O load across as many disks as possible by manually striping the tablespace's datafiles across all these disks.
Your backup media doesn't have much capacity and its more efficient to manage with one small datafile per media backup unit.
Your O/S doesn't manage files larger than 100Mb very well or at all.
You are using a good disk defragmentation software that actually records statistics on file usage and reorganises 'hot' files on the disk for fastest access to hottest files. Having a tablespace in multiple datafiles per disk will allow this sort of defragmenting to work most efficiently.

Bruce...

   T T T T T T T T        Bruce Pihlamae
   I I I I I I I I        bpihlama_at_nla.gov.au
   I I I I I I I I        National Library of Australia
   T T T T T T T T        Phone: +616 262-1480
  -----------------       Fax:   +616 273-2116
 ===================

"If you swallow a live frog first thing in the morning; nothing worse will happen to either of you that day." Received on Sun Jan 21 1996 - 17:14:16 CST