Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 153F564FD2E for ; Thu, 6 Nov 2008 14:46:59 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 18194-08 for ; Thu, 6 Nov 2008 14:46:58 -0400 (AST) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from yx-out-2324.google.com (yx-out-2324.google.com [74.125.44.29]) by mail.postgresql.org (Postfix) with ESMTP id 901406500B4 for ; Thu, 6 Nov 2008 14:46:57 -0400 (AST) Received: by yx-out-2324.google.com with SMTP id 8so328876yxb.73 for ; Thu, 06 Nov 2008 10:46:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=93attBgpE2gOKya0zLxOSiKeFv/ugYe9uqyLleJy/Oc=; b=N49rQFovPEId0k4MdWP8/uhpplSWEk2Bh1uZGi5Ew95E5R0+HtsNeXKNpmbSnoTtLJ dZmaTnj9BHYbrcj42714HCfbb19zg+sS7eSwjtc3bmrTSY2Ws6a8LFfDqMhtyW1gw7pY vGtqC5HWfot4Ty2UbvMcizD88Vl8RglLAx/oU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=ko4ulhTqgu7D/OvHMM6PeiqCSnKx1wlGn3wWtuuh5PkFkilUgJ7gX+yJituTipYML9 VjiNHDOoAb4hnvFVPCdK4X2aJ4AnP69ox1atSNN99641epTt4ZbT1SmDqQKdSCP+OUxB swspYDKjQrZO/+UxVObe2I7QkeslD6UIwRu34= Received: by 10.151.155.21 with SMTP id h21mr1871768ybo.70.1225997216397; Thu, 06 Nov 2008 10:46:56 -0800 (PST) Received: by 10.150.211.9 with HTTP; Thu, 6 Nov 2008 10:46:56 -0800 (PST) Message-ID: <72dbd3150811061046w4fdcd9bbnf78459b9dffd566d@mail.gmail.com> Date: Thu, 6 Nov 2008 10:46:56 -0800 From: "David Rees" To: "Scott Marlowe" Subject: Re: Occasional Slow Commit Cc: "Peter Schuller" , pgsql-performance@postgresql.org In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <72dbd3150810271723w57859013v9c4e3718ae86fba@mail.gmail.com> <72dbd3150810291530q7a95da64j2c39354de9ad91d1@mail.gmail.com> <72dbd3150810311714s51639bc3kfdbe03a7b51bc55c@mail.gmail.com> <72dbd3150811051925n50ead40cn30354990ebb8bfb6@mail.gmail.com> <20081106102147.GB70379@hyperion.scode.org> <72dbd3150811060747u7f3c2aadv3c6658d285d74455@mail.gmail.com> X-Archive-Number: 200811/33 X-Sequence-Number: 31764 On Thu, Nov 6, 2008 at 8:07 AM, Scott Marlowe wrote: > On Thu, Nov 6, 2008 at 8:47 AM, David Rees wrote: >> >> In the case of the machines without a BBU on them, they are configured >> to be in WriteBack, but are actually running in WriteThrough. > > I'm pretty sure the LSIs will refuse to actually run in writeback without a BBU. It's configurable (at least on the MegaRAID cards I'm using). There's an option you can turn on that lets you run in writeback when the BBU is offline. -Dave