Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id DEDFC2E2EE8 for ; Mon, 26 Nov 2007 19:01:00 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 48657-03 for ; Mon, 26 Nov 2007 19:00:55 -0400 (AST) Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.179]) by postgresql.org (Postfix) with ESMTP id 24F4D2E0188 for ; Mon, 26 Nov 2007 19:00:54 -0400 (AST) Received: by wa-out-1112.google.com with SMTP id m38so1123386waf for ; Mon, 26 Nov 2007 15:00:53 -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=01JJWteMng+BKBNF8K8wJHWWc7BU3w4xp5sIPsf2S2Y=; b=uttJScFempngAE6ovBRFneyfTwBDZPQhhv1yvr6eeztz59/IT7rud22Gcds/I3hP7T2cVNDyCMUVlBu0JQORUC5LLL7ce3OA2+MSBdjUk31TPvlh7TIZ9sP8pOOzNqrME5nmLJIhc7cPQPxw9/RgAL14ZeHU5s+DaxDKg/ARiWg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=mXr3m4J+UQV0FuHS32Lmeo+Rkks+qNIbUrtI0SBVBQ6+frOB+bOJKuwLy9cVz5XbizAFx3B54GOM3Y2MEabgpA3WAeBKeLFJ8k+i59ceXBaYTPmZU+jrM93ZR5+2zyOU+mMFZaYC/B3XyvP97Bg0Xpr6E319N1qvcW2VZCY+Vls= Received: by 10.114.196.1 with SMTP id t1mr420844waf.1196118053596; Mon, 26 Nov 2007 15:00:53 -0800 (PST) Received: by 10.114.53.7 with HTTP; Mon, 26 Nov 2007 15:00:53 -0800 (PST) Message-ID: Date: Mon, 26 Nov 2007 17:00:53 -0600 From: "Scott Marlowe" To: "Damon Hart" Subject: Re: PostgreSQL performance on various distribution stock kernels Cc: pgsql-performance@postgresql.org In-Reply-To: <1196117408.19996.16.camel@xw1.bbd> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1196117408.19996.16.camel@xw1.bbd> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200711/309 X-Sequence-Number: 27724 On Nov 26, 2007 4:50 PM, Damon Hart wrote: > > So, what's different between these tests? I'm seeing performance > differences of between +65% to +90% transactions per second of the > OpenVZ kernel running on the HN over the stock Fedora 8 kernel. Is > this reflective of different emphasis between RHEL and Fedora kernel > builds? Some OpenVZ optimization on top of the RHEL5 build? Something > else? Where should I look? > > any insights much appreciated, How many TPS are you seeing on each one? If you are running 10krpm drives and seeing more than 166.66 transactions per second, then your drives are likely lying to you and not actually fsyncing, and it could be that fsync() on IDE / SATA has been implemented in later kernels and it isn't lying. Hard to say for sure. What does vmstat 1 have to say on each system when it's under load?