Received: from maia.hub.org (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 28F2263263C for ; Mon, 22 Feb 2010 21:15:24 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 77251-01-2 for ; Tue, 23 Feb 2010 01:15:06 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.186]) by mail.postgresql.org (Postfix) with ESMTP id 275306349B7 for ; Mon, 22 Feb 2010 21:14:52 -0400 (AST) Received: from [192.168.0.105] (pool-96-244-14-10.bltmmd.fios.verizon.net [96.244.14.10]) by mrelayeu.kundenserver.de (node=mreu1) with ESMTP (Nemesis) id 0MDl62-1NzeTf0QJy-00HHyc; Tue, 23 Feb 2010 02:14:50 +0100 Message-ID: <4B832C07.60301@2ndquadrant.com> Date: Mon, 22 Feb 2010 20:14:47 -0500 From: Greg Smith User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Ron Mayer CC: Bruce Momjian , pgsql-performance Subject: Re: SSD + RAID References: <201002221437.o1MEbDJ13005@momjian.us> <4B82C642.8020409@cheapcomplexdevices.com> In-Reply-To: <4B82C642.8020409@cheapcomplexdevices.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V01U2FsdGVkX1+u9HghCylYmGjv6rYb/CnjfpS7HMC5HsulAyt 9WTRTjI5eSq/CNoOGjPfo4CPW49gP0aG19o1F2lRbN1wJub1jj WVGpfBBE2nyBi9QPQYZaI2Q1bHcdrqV X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.428 tagged_above=-10 required=5 tests=AWL=0.171, BAYES_00=-2.599 X-Spam-Level: X-Archive-Number: 201002/309 X-Sequence-Number: 37730 Ron Mayer wrote: > I know less about other file systems. Apparently the NTFS guys > are aware of such stuff - but don't know what kinds of fsync equivalent > you'd need to make it happen. > It's actually pretty straightforward--better than ext3. Windows with NTFS has been perfectly aware how to do write-through on drives that support it when you execute _commit for some time: http://msdn.microsoft.com/en-us/library/17618685(VS.80).aspx If you switch the postgresql.conf setting to fsync_writethrough on Windows, it will execute _commit where it would execute fsync on other platforms, and that pushes through the drive's caches as it should (unlike fsync in many cases). More about this at http://archives.postgresql.org/pgsql-hackers/2005-08/msg00227.php and http://www.westnet.com/~gsmith/content/postgresql/TuningPGWAL.htm (which also covers OS X). -- Greg Smith 2ndQuadrant US Baltimore, MD PostgreSQL Training, Services and Support greg@2ndQuadrant.com www.2ndQuadrant.us