That is why RAID-0 striping is generally combined with RAID-1 mirroring, so that the load is distributed amongst more than just the single set of mirrored devices. RAID-5 is simply a trade-off of performance for capacity, any way you cut it... RAID-1 is redundancy with no compromise in performance. Plain and simple... -- Attached file included as plaintext by Ecartis -- -- File: RE: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS Return-Path: <oracle-l-bounce@xxxxxxxxxxxxx> Received: from mail.sagelogix.com by ocs.sagelogix.com with ESMTP id 32534541093465996; Wed, 25 Aug 2004 14:33:16 -0600 Received: by mail.sagelogix.com (Postfix, from userid 16) id A7793A84A3; Wed, 25 Aug 2004 14:25:27 -0600 (MDT) Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by mail.sagelogix.com (Postfix) with ESMTP id 77BB8A83A3 for <tim@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 14:23:11 -0600 (MDT) Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id DE8EA72E9EC; Wed, 25 Aug 2004 15:27:27 -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 20923-63; Wed, 25 Aug 2004 15:27:27 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id C632672C651; Wed, 25 Aug 2004 15:21:24 -0500 (EST) Received: with ECARTIS (v1.0.0; list oracle-l); Wed, 25 Aug 2004 15:19:59 -0500 (EST) X-Original-To: oracle-l@xxxxxxxxxxxxx Delivered-To: oracle-l@xxxxxxxxxxxxx Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 6367272E7AE for <oracle-l@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 15:17:27 -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 18624-86 for <oracle-l@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 15:17:27 -0500 (EST) Received: from smtp2.smith.com (smtp2.smith.com [63.149.135.12]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 599C572D6C4 for <oracle-l@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 15:12:35 -0500 (EST) Received: from 172.21.21.244 by smtp2.smith.com with ESMTP ( (MMS v5.6.3 )); Wed, 25 Aug 2004 15:14:09 -0500 X-Server-Uuid: 6429C5EE-306C-482B-A842-D75C76A1DB7A Received: from siihardyxch01.net.smith.com ([172.21.21.241]) by siihardyxch04.net.smith.com with Microsoft SMTPSVC(5.0.2195.6713); Wed, 25 Aug 2004 15:14:02 -0500 Received: from midhouhqxch01.net.smith.com ([172.20.80.213]) by siihardyxch01.net.smith.com with Microsoft SMTPSVC(5.0.2195.6713); Wed, 25 Aug 2004 15:13:40 -0500 X-MimeOLE: Produced By Microsoft Exchange V6.0.6556.0 content-class: urn:content-classes:message MIME-Version: 1.0 Subject: RE: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS Date: Wed, 25 Aug 2004 15:14:01 -0500 Message-ID: <7E0DB3A126BA9146AC30744E2B7E42459743CF@xxxxxxxxxxxxxxxxxxxxxxxxxxx> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS Thread-Index: AcSK3fJTY/oZZvceT2yqviGf/+7YPgAAbbyA From: "Nelson, Allan" <anelson@xxxxxxxxxxx> To: oracle-l@xxxxxxxxxxxxx X-OriginalArrivalTime: 25 Aug 2004 20:13:40.0171 (UTC) FILETIME=[030D09B0:01C48AE0] X-WSS-ID: 6D322D7326G157684-07-01 Content-type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit X-Virus-Scanned: by amavisd-new at freelists.org X-archive-position: 8346 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@xxxxxxxxxxxxx Errors-To: oracle-l-bounce@xxxxxxxxxxxxx X-original-sender: anelson@xxxxxxxxxxx Precedence: normal Reply-To: oracle-l@xxxxxxxxxxxxx X-list: oracle-l X-Virus-Scanned: by amavisd-new at freelists.org X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on mail.sagelogix.com X-Spam-Status: No, hits=0.2 required=3.0 tests=EXCUSE_16 autolearn=no version=2.63 X-Spam-Level: Raid 5 does get good read performance because for reads more disks get in on the action. 3 in his example vs essentially 2 for the raid 0+1 stuff. Allan -----Original Message----- =46rom: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of tim@xxxxxxxxxxxxx Sent: Wednesday, August 25, 2004 2:16 PM To: oracle-l@xxxxxxxxxxxxx Subject: Re: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS Deen, How can RAID-5 perform better than RAID-1 (especially 1+0) on reads=3F That's a new one I've not heard before. Oh, and writes=3F Don't worry about them -- we've got caching so it doesn't matter! <rant> Oh yes, the old "we've got so much cache it doesn't matter". Don't believe it: cache has to be managed (possible source of contention) and cache can be overwhelmed. At best, cache smoothes out the spikes, but it cannot help during a prolonged period of high activity. I don't know why Sun thinks that there is a market for things like =66ile-systems, but I've heard them waste hours trying to convince folks to use their wonderful new UFS (yawn!). At a large financial institution last May, I participated in an Oracle-based benchmark with =66our scenarios: "regular" UFS (i.e. no direct I/O), UFS with direct I/O, VxFS, and VxFS with "quick I/O" (now called ODM). Then, for kicks, the sys-admins and I added an "illegal" scenario -- "raw" logical volumes -- to the mix. The turd in the punch-bowl, the black sheep of the storage family, the fifth option that none of the vendors wanted to talk about. We boiled each of the benchmark results down to a single metric for relative comparison, with the first option (plain UFS) at a score of 22, VxFS with 18, UFS with direct I/O also at 17-18, VxFS with QIO/ODM at 12-13, and "raw" devices at 9. Of course, because the use of "raw" devices were "banned" from the competition (=3F), Veritas got their sale. Nev ermind we were using VxVM for the logical volumes... :-) I count this as the best feat of marketing since Coke and Pepsi convinced everyone that "soft drinks" are a part of daily life, adding ump-teen layers of additional software to arrive a result that is measurably less than simply removing the whole kit-and-kaboodle. Paraphrasing the movie "Blazing Saddles": "File-systems=3F We don't need no stinking file-systems...", but often that attitude is rather like =66arting at the reception. </rant mode=3D"scuttles back into cave, pulls stone shut"> Hope this helps... -Tim -- Attached file included as plaintext by Ecartis -- -- File: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS Return-Path: <oracle-l-bounce@xxxxxxxxxxxxx> Received: from mail.sagelogix.com by ocs.sagelogix.com with ESMTP id 32465831093458022; Wed, 25 Aug 2004 12:20:22 -0600 Received: by mail.sagelogix.com (Postfix, from userid 16) id 2F445A85F9; Wed, 25 Aug 2004 12:12:44 -0600 (MDT) Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by mail.sagelogix.com (Postfix) with ESMTP id 4391BA85EA for <tim@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 12:12:42 -0600 (MDT) Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 8405472EF75; Wed, 25 Aug 2004 13:17:47 -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 32243-30; Wed, 25 Aug 2004 13:17:47 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 1B21072F346; Wed, 25 Aug 2004 13:17:08 -0500 (EST) Received: with ECARTIS (v1.0.0; list oracle-l); Wed, 25 Aug 2004 13:15:38 -0500 (EST) X-Original-To: oracle-l@xxxxxxxxxxxxx Delivered-To: oracle-l@xxxxxxxxxxxxx Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 2B6BC72C66A for <oracle-l@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 13:15:36 -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 30855-90 for <oracle-l@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 13:15:36 -0500 (EST) Received: from xmail2.state.nj.us (xmail2.state.nj.us [199.20.71.249]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 0473872DC48 for <oracle-l@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 13:15:35 -0500 (EST) Received: from mail2av.state.nj.us (mail2av.state.nj.us [10.34.20.40]) by xmail2.state.nj.us (8.12.9/8.12.11) with SMTP id i7PIHVZs016591 for <oracle-l@xxxxxxxxxxxxx>; Wed, 25 Aug 2004 14:17:31 -0400 (EDT) Received: from revere.dol.state.nj.us(199.20.109.30) by mail2av.state.nj.us via csmap=20 id 07825dac_f6c3_11d8_8c24_00304811e4b6_16026; Wed, 25 Aug 2004 14:17:31 -0400 (EDT) Received: from W00DIT7NRQ721 ([10.6.161.115]) by revere.dol.state.nj.us (iPlanet Messaging Server 5.2 HotFix 1.08 (built Dec 6 2002)) with ESMTP id <0I3000IEMLH6TI@xxxxxxxxxxxxxxxxxxxxxx> for oracle-l@xxxxxxxxxxxxx; Wed, 25 Aug 2004 14:17:30 -0400 (EDT) Date: Wed, 25 Aug 2004 14:17:30 -0400 =46rom: Deen Dayal <deen.dayal@xxxxxxxxxxxxxxx> Subject: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS In-reply-to: <00ac01c48ab5$993927f0$8459000a@xxxxxxxxxxxxxxxxxxxxxxxx> To: oracle-l@xxxxxxxxxxxxx Message-id: <0I3000IENLH6TI@xxxxxxxxxxxxxxxxxxxxxx> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-Mailer: Microsoft Office Outlook, Build 11.0.5510 Content-type: text/plain; charset=3Dus-ascii Content-Transfer-Encoding: 8bit Thread-index: AcSKuItdQm7LqJ43Thm15SQ9h9zK9QAANqYA X-Virus-Scanned: by amavisd-new at freelists.org X-archive-position: 8336 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@xxxxxxxxxxxxx Errors-To: oracle-l-bounce@xxxxxxxxxxxxx X-original-sender: deen.dayal@xxxxxxxxxxxxxxx Precedence: normal Reply-To: oracle-l@xxxxxxxxxxxxx X-list: oracle-l X-Virus-Scanned: by amavisd-new at freelists.org X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on mail.sagelogix.com X-Spam-Status: No, hits=3D0.0 required=3D3.0 tests=3Dnone autolearn=3Dno version=3D2.63 X-Spam-Level:=20 We are planning to move our current database to new Hardware Sun 12k + Hitachi SE 9970.=20 Our current database runs on Sun A5000 array with Raid0+1 on raw devices. Sun engineer who is here at our site for implementation of Hitachi SE9970 suggests that we should go Raid5 ( 3 + 1P ) in the parity group as RAID5 gives better read performance than raid0+1 and any writes are going to the cache any way, so we should not be worried about write performance. There is 16GB cache on the Hitachi. Database is going to be striped across 10 parity groups and each parity group consists of 4 physical disks. Our application is about 60 to 70% reads most of the time, kind of a DSS and for few batch jobs it is 90% write and 10% read. Database is not that big just 200GB. He also suggested us to use UFS instead of RAW as Solaris 9 has lot improvements in UFS especially with Concurrent Direct I/O and can perform better than RAW. I am wondering anybody out there with real world experience with similar Hardware can throw some light on these 2 topics. If anybody can point any links or documents discussing these topics, highly appreciated. Thanks Deen ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ =46AQ is at //www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ =46AQ is at //www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ___________________________________________________________________________= ___ This email is intended solely for the person or entity to which it is = addressed and may contain confidential and/or privileged information. = Copying, forwarding or distributing this message by persons or entities = other than the addressee is prohibited. 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