X-Original-To: pgsql-general-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 1F61E9FA92E; Wed, 10 May 2006 11:38:21 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 05716-08; Wed, 10 May 2006 11:38:07 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.logix-tt.com (unknown [212.211.145.186]) by postgresql.org (Postfix) with ESMTP id 0C6A19FA32D; Wed, 10 May 2006 11:38:07 -0300 (ADT) Received: from kingfisher.intern.logix-tt.com (p549D13DA.dip0.t-ipconnect.de [84.157.19.218]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.logix-tt.com (Postfix) with ESMTP id 5AA8A65837; Wed, 10 May 2006 16:39:17 +0200 (CEST) Received: from [127.0.0.1] (localhost [127.0.0.1]) by kingfisher.intern.logix-tt.com (Postfix) with ESMTP id 2CE6C18222EEA; Wed, 10 May 2006 16:38:18 +0200 (CEST) Message-ID: <4461FAD9.6020106@logix-tt.com> Date: Wed, 10 May 2006 16:38:17 +0200 From: Markus Schaber Organization: Logical Tracking and Tracing International AG, Switzerland User-Agent: Debian Thunderbird 1.0.7 (X11/20051017) X-Accept-Language: en-us, en MIME-Version: 1.0 To: PostgreSQL General Cc: "Pgsql-Performance ((E-mail))" Subject: Re: [PERFORM] Arguments Pro/Contra Software Raid References: <200605101401.k4AE1XQ08859@candle.pha.pa.us> In-Reply-To: <200605101401.k4AE1XQ08859@candle.pha.pa.us> X-Enigmail-Version: 0.93.0.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/432 X-Sequence-Number: 95224 Hi, Bruce, Bruce Momjian wrote: >>It does not find as much liers as the script above, but it is less > > Why does it find fewer liers? It won't find liers that have a small "lie-queue-length" so their internal buffers get full so they have to block. After a small burst at start which usually hides in other latencies, they don't get more throughput than spindle turns. It won't find liers that first acknowledge to the host, and then immediately write the block before accepting other commands. This improves latency (which is measured in some benchmarks), but not syncs/write rate. Both of them can be captured by the other script, but not by my tool. HTH, Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org