Re: Creating DB on partition > 2TB

From: Mark Brinsmead <>
Date: Thu, 6 Mar 2008 19:06:26 -0700
Message-ID: <>

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 <> wrote:

> Sounds like a DBCA bug from a really large number. Oracle db doesn't
> 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 4,
> > 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 - 20:06:26 CST

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