Re: Defrag tool on the Oracle database server

From: Nuno Souto <dbvision_at_optusnet.com.au>
Date: Tue, 10 Feb 2004 21:13:56 +1100
Message-ID: <017a01c3efbe$c2504110$9b00a8c0@dcs001>

• Original Message ----- From: "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> >
  > Yes, NTFS is most definitely susceptible to fragmentation - in the sense
  th=
  > at a single datafile may get split into multiple pieces all over the shop.
  =
  > If you have an NT based laptop take a look at the disk using the disk
  defra=
  > gmenter in administrative tools (you can just run an analyze and not
  actual=
  > ly do any defragmenting).=20
  

And these things, like most others in NTFS, are fully configurable. For those interested, I do recommend reading the FULL description of the "fsutil" command. New in XP, I believe it was there in W2K Pro and ES but undocumented. It allows you to trim/control/configure most of these file system parameters.

Some are VERY relevant to Oracle.

This is an interesting tech note in the M$ website: http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/winntas/maintain/optimize/instant.asp

watch out for wrapping, try this if all else fails: http://tinyurl.com/27sgv

And of course, don't forget:
http://tinyurl.com/elct
if you REALLY want to bump up those DFMBR read sizes for FTS! This last one also has a bearing on the minimal portion/fragment that a file can be split into at create time, although I've only seen that described outside of M$ (undoco?).

Don't forget one very important thing: BY DEFAULT, NTFS is configured to provide optimal "file server" functionality. That's HEAPS of SMALL files, in the Queen's language.

Nothing could be more removed from the reality of Oracle db files: FEW, VERY LARGE files.

So, be prepared for heaps of tuning/configuring. And for Pete's sake (or any other of Pete's drinks that turn you on), do NOT create Oracle database files in anything other than a freshly formatted NTFS partition!!!!!

To their credit, M$ nowadays provides incredible amounts of doco of good to very good quality in their site. That was not always the case...

Or, take the easy way out: install 10g, give it unformatted (raw) partition(s) to manage and be done with all these problems. (and if you believe that, you're really brave...) :D

Cheers
Nuno Souto
in sunny Sydney, Australia
dbvision_at_optusnet.com.au

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Received on Tue Feb 10 2004 - 04:13:56 CST