From oracle-l-bounce@freelists.org Thu Oct 20 22:17:18 2005 Return-Path: Received: from air891.startdedicated.com (root@localhost) by orafaq.com (8.12.10/8.12.10) with ESMTP id j9L3H8sT016026 for ; Thu, 20 Oct 2005 22:17:13 -0500 X-ClientAddr: 206.53.239.180 Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by air891.startdedicated.com (8.12.10/8.12.10) with ESMTP id j9L3GsvX015994 for ; Thu, 20 Oct 2005 22:16:54 -0500 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 3CD8920A64D; Thu, 20 Oct 2005 22:16:42 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 15732-04; Thu, 20 Oct 2005 22:16:42 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 64E7220A5F5; Thu, 20 Oct 2005 22:16:41 -0500 (EST) X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C5D5ED.8E1661B5" Subject: RE: Linux 2.6 I/O Scheduler & ASM/Raw Date: Thu, 20 Oct 2005 20:14:31 -0700 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Linux 2.6 I/O Scheduler & ASM/Raw Thread-Index: AcXV2NUIbrPotYAuQB+2nPBpKi2yPgAFM+1w From: "Kevin Closson" To: "Oracle Mailing List" X-archive-position: 27310 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-To: oracle-l-bounce@freelists.org X-original-sender: kevinc@polyserve.com Precedence: normal Reply-To: kevinc@polyserve.com X-list: oracle-l X-Virus-Scanned: by amavisd-new-20030616-p9 (Debian) at avenirtech.net X-mailscan-MailScanner-Information: Please contact the ISP for more information X-mailscan-MailScanner: Found to be clean X-MailScanner-From: oracle-l-bounce@freelists.org X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on air891.startdedicated.com X-Spam-Level: X-Spam-Status: No, hits=-4.7 required=5.0 tests=AWL,BAYES_00, HTML_FONTCOLOR_BLUE,HTML_MESSAGE autolearn=no version=2.63 ------_=_NextPart_001_01C5D5ED.8E1661B5 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable how do you suppose a linux process is going to perform I/O=20 without a system call? ASM I/O is either simply libC, LibODM or ASMlib on Linux (which is still implemented in Kernel mode). =20 yes yes, I know about that goofy DAFS stuff that never saw the light of day. ________________________________ From: oracle-l-bounce@freelists.org [mailto:oracle-l-bounce@freelists.org] On Behalf Of Murching, Bob Sent: Thursday, October 20, 2005 5:46 PM To: 'Oracle Mailing List' Subject: Linux 2.6 I/O Scheduler & ASM/Raw =09 =09 Apologies in advance for the simple question but if a database uses raw or ASM storage, is it bypassing the operating system's I/O layer, or not? For example, should the choice of scheduler (cfq, as, noop, deadline) in the Linux 2.6 affect performance of an ASM or RAW filesystem, or should it not? Likewise, are variables such as the maximum I/O size at an OS level (e.g. 512KB or 1M) and the OS block size (8KB, 16KB, ...) still meaningful with raw filesystems? I suspect the answer to both questions is "yes" but I'm not sure and haven't seen this spelled out clearly....=20 Bob=20 ------_=_NextPart_001_01C5D5ED.8E1661B5 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Linux 2.6 I/O Scheduler & ASM/Raw
how do you suppose a linux process is going = to perform=20 I/O
without a system call?  ASM I/O is = either simply=20 libC, LibODM or
ASMlib on Linux (which is still implemented = in Kernel=20 mode).
 
yes yes, I know about that goofy DAFS stuff = that never=20 saw
the light of day.


From: = oracle-l-bounce@freelists.org=20 [mailto:oracle-l-bounce@freelists.org] On Behalf Of Murching,=20 Bob
Sent: Thursday, October 20, 2005 5:46 PM
To: = 'Oracle=20 Mailing List'
Subject: Linux 2.6 I/O Scheduler &=20 ASM/Raw

Apologies in advance for the simple = question but if=20 a database uses raw or ASM storage, is it bypassing the operating = system's I/O=20 layer, or not?  For example, should the choice of scheduler (cfq, = as,=20 noop, deadline) in the Linux 2.6 affect performance of an ASM or RAW=20 filesystem, or should it not?  Likewise, are variables such as = the=20 maximum I/O size at an OS level (e.g. 512KB or 1M) and the OS block = size (8KB,=20 16KB, ...) still meaningful with raw filesystems?

I suspect the answer to both questions = is "yes" but=20 I'm not sure and haven't seen this spelled out clearly....

Bob =

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