Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id 423EF6325B9 for ; Mon, 10 May 2010 11:48:15 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 74022-03 for ; Mon, 10 May 2010 14:48:06 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mx1.partiallystapled.com (unknown [72.37.225.168]) by mail.postgresql.org (Postfix) with ESMTP id 798E0632BCC for ; Mon, 10 May 2010 11:48:08 -0300 (ADT) Received: by mx1.partiallystapled.com (Postfix, from userid 131) id 0EBDC12B4E; Mon, 10 May 2010 14:48:04 +0000 (UTC) Received: from eureka.rdu.rpath.com (unknown [66.192.95.199]) (Authenticated sender: gxti) by mx1.partiallystapled.com (Postfix) with ESMTPSA id 1DDCA12B4D; Mon, 10 May 2010 14:48:02 +0000 (UTC) Message-ID: <4BE81CA1.4080201@partiallystapled.com> Date: Mon, 10 May 2010 10:48:01 -0400 From: Michael Tharp User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Craig Ringer CC: pgsql-hackers@postgresql.org Subject: Re: no universally correct setting for fsync References: <4BE3D3930200002500031382@gw.wicourts.gov> <4BE425F7.30804@dunslane.net> <4BE3E205020000250003138F@gw.wicourts.gov> <4BE4543D.8010309@agliodbs.com> <4BE51BA5.70202@postnewspapers.com.au> In-Reply-To: <4BE51BA5.70202@postnewspapers.com.au> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.107 tagged_above=-5 required=5 tests=BAYES_00=-1.9, RDNS_NONE=0.793 X-Spam-Level: X-Archive-Number: 201005/461 X-Sequence-Number: 162124 On 05/08/2010 04:07 AM, Craig Ringer wrote: > It's probably worth mentioning that people who want to turn off fsync to > gain a performance boost should instead look at a RAID controller with a > BBU so they can safely enable write-back caching, getting most of the > benefits of fsync=off safely. Which options specifically should be set if a BBU is in use? Obviously fsync should be on always, but can full_page_writes be disabled? Are there other tweaks that can be done? It would be great to see some practical hints in the documentation while the fsync part is getting changed. -- m. tharp