From kchan@speednet.com.au Tue, 19 Jun 2001 17:31:30 -0700
From: "KC" <kchan@speednet.com.au>
Date: Tue, 19 Jun 2001 17:31:30 -0700
Subject: Re: Disk configuration
Message-ID: <F001.0032F608.20010619165055@fatcity.com>
MIME-Version: 1.0
Content-Type: text/plain




Kevin,
 
Thanks for your input. I was trying to put certain 
datafiles on contiguous disk space, tell me if I am wrong, I try to avoid the 
situation where you want to create a 2G file, but the file system don't have a 
2G contiguous space, so your flle is broken into multiple pieces, can that 
happen??
 
KC
<BLOCKQUOTE 
style="BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">
    -----Original Message-----From: 
    Kevin Lange <<A 
    href="mailto:kgel@ppoone.com">kgel@ppoone.com>To: Multiple 
    recipients of list ORACLE-L <<A 
    href="mailto:ORACLE-L@fatcity.com">ORACLE-L@fatcity.com>Date: 
    Wednesday, June 20, 2001 1:22 AMSubject: RE: Disk 
    configuration
    It 
    all depends on what kind of os/filesystem/and disks you have.   I 
    know that under AIX, using SSA drives we could actually tell where on the 
    disk we wanted the filesystem to go.  This way we could position 
    certain things in the faster location.  
    <FONT color=#0000ff face=Arial 
    size=2> 
    <FONT color=#0000ff face=Arial 
    size=2>But personally, I would not go thru the trouble.
    <FONT color=#0000ff face=Arial 
    size=2> 
    I 
    have never had a DB slowdown so far because of placement on the 
    drive.   Admittadly, I have had probelms based on putting 
    conflicting tables/indexes on the same drive .... you want to keep things 
    that could be access simultaneously on  different media.  But 
    other than that ....  no other conflicts.
    
        <FONT face=Tahoma 
        size=2>-----Original Message-----From: KC 
        [mailto:kchan@speednet.com.au]Sent: Tuesday, June 19, 2001 
        9:36 AMTo: Multiple recipients of list 
        ORACLE-LSubject: Disk configuration
        Dear List,
         
        Someone told me when a disk 
        receive a write request, it write to the nearest free space on disk 
        where the disk read/write head is currently positioning, is this 
        information correct?? If this is true, is this a bad thing for database 
        application?? That mean we can't really control where the file go, for 
        performance purpose we may want to put certain files on the outer tracks 
        of a disk, if the write location is depending on where the read/write 
        head is, how can we avoid that, can we create subdisks from the outer 
        track of a disk and create a logical volume from it??
         
        <FONT color=#000000 face=Arial 
size=2>KC