From oracle-l-bounce@freelists.org Mon Jul 26 13:14:33 2004 Return-Path: Received: from air189.startdedicated.com (root@localhost) by orafaq.com (8.11.6/8.11.6) with ESMTP id i6QIEIL01189 for ; Mon, 26 Jul 2004 13:14:28 -0500 X-ClientAddr: 206.53.239.180 Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by air189.startdedicated.com (8.11.6/8.11.6) with ESMTP id i6QIE8601030 for ; Mon, 26 Jul 2004 13:14:18 -0500 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 1F91E72CE99; Mon, 26 Jul 2004 12:52:40 -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 01327-96; Mon, 26 Jul 2004 12:52:39 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 6731372CE90; Mon, 26 Jul 2004 12:52:39 -0500 (EST) Received: with ECARTIS (v1.0.0; list oracle-l); Mon, 26 Jul 2004 12:51:13 -0500 (EST) X-Original-To: oracle-l@freelists.org Delivered-To: oracle-l@freelists.org Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 0B15972C7DE for ; Mon, 26 Jul 2004 12:51:13 -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 00606-94 for ; Mon, 26 Jul 2004 12:51:12 -0500 (EST) Received: from web50107.mail.yahoo.com (web50107.mail.yahoo.com [206.190.38.35]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with SMTP id 2C09C72CC4F for ; Mon, 26 Jul 2004 12:51:12 -0500 (EST) Message-ID: <20040726181801.45999.qmail@web50107.mail.yahoo.com> Received: from [151.138.254.21] by web50107.mail.yahoo.com via HTTP; Mon, 26 Jul 2004 11:18:01 PDT Date: Mon, 26 Jul 2004 11:18:01 -0700 (PDT) From: Kirtikumar Deshpande Subject: Re: "free buffer waits" under eXtreme Transaction Loads To: oracle-l@freelists.org In-Reply-To: <381a01c47338$e18acf70$0a879fd9@porgand> MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii X-Virus-Scanned: by amavisd-new at freelists.org Content-Transfer-Encoding: 8bit X-archive-position: 6031 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-To: oracle-l-bounce@freelists.org X-original-sender: kedeshpande@yahoo.com Precedence: normal Reply-To: oracle-l@freelists.org X-list: oracle-l X-Virus-Scanned: by amavisd-new at freelists.org Also, are your sql statements performing unnecessary physical I/O? Can those be tuned to reduce it? But, implement one solution at a time, though, to see what impact it has. Regards, - Kirti --- Tanel_Põder wrote: > > How are "free buffer waits" (below) to be addressed? > > Your DBWR probably isn't able to write dirty buffers to disk fast enough. > > See if you have disk_asynch_io = true set. > If you're running on regular cooked filesystem (not QuickIO) then you should > probably increase the number of db writer processes or dbwr slaves (instead > of using OS simulated asynch IO). > > Btw, if you are on raw devices or QuickIO and using kernelized asynch IO, I > would still keep the number of dbwr's greater than 1 in heavily IO intensive > environment. > > Also, number of buffer cache LRU latches (controlled by > _db_block_lru_latches) might become a bottleneck in your env (lots of CPUs + > heavy IO). > > Also, you might want to increase your buffer cache (tm ;) to give dbwr a > little more breathing room. > > Btw, why do you want to have separate 4 controllers for log files? I get the > need for 2 ones (the IO generated by archiver won't disturb lgwr's IO), but > why the additional 2? Just for having more time for archiver before lgwr > hits the same controller again or are you using software striping over > different controllers (or multiplexing) for redologs? > > Tanel. > > > ---------------------------------------------------------------- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > ---------------------------------------------------------------- > To unsubscribe send email to: oracle-l-request@freelists.org > put 'unsubscribe' in the subject line. > -- > Archives are at http://www.freelists.org/archives/oracle-l/ > FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html > ----------------------------------------------------------------- > __________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. 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