RE: Creating DB on partition > 2TB

From: William Wagman <>
Date: Thu, 6 Mar 2008 18:10:38 -0800
Message-ID: <>


That makes a lot of sense. I just need to convince the requestors.  


Bill Wagman
Univ. of California at Davis
IET Campus Data Center
(530) 754-6208  

From: Mark Brinsmead [] Sent: Thursday, March 06, 2008 6:06 PM
To:; William Wagman Cc:
Subject: Re: Creating DB on partition > 2TB

I have to agree with Greg here. There are other things to consider beyond (just) IO performance, too.

There is also the question of recover time should come up here as well. In building a single LUN (or filesystem, or...) of 3TB, this becomes the amount of data you will -- or at least may -- have to recover in the even of a serious failure.

Before you say "I have RAID protection at the hardware level", let me ask this: Have you even seen somebody reformat the wrong disk, or do rm -rf in the wrong filesystem? I know I have! (Seen it, that is. I've never actually done that. Oh, no, no, no...) :-)

Even in cases where you do have hardware RAID support (and you actually believe the B.S. that the salesrep pushed about his RAID product being infallible) there are still plenty of failure modes that can result in the need to restore data to an entire LUN or filesystem.

Compartmentalizing your data may not prevent such accidents, but it can at least help to restrict the scope of the damage, and perhaps put you in a position where you only need to restore 100GB of data from tape, instead of the while 3TB.

(Yeah, yeah, I know: you don't plan to use the whole 3 TB. Yet!)

-- Mark Brinsmead
  Senior DBA,
  The Pythian Group

On Thu, Mar 6, 2008 at 4:08 PM, Greg Rahn <>

	Sounds like a DBCA bug from a really large number.  Oracle db
	have any knowledge of the LUN size, only database file size.
	I don't know that I would recommend just a single large LUN.  I
	believe that things like the SCSI IO queue are per LUN so with
only a
	single LUN you only get one queue.  This probably will limit the
	number of in-flight IOs.

	On 3/6/08, William Wagman <> wrote:

> Greetings,
> I have installed Oracle on a server running Centos
> 2.6.9-67.0.4.Elsmp. This is a new server and installation. I
am using
> the DBCA to create the database which initially will only be
2GB. The
> partition on which I am attempting to create the database has
nearly 3TB
> of space and ..
<> --
Received on Thu Mar 06 2008 - 20:10:38 CST

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