From owner-freebsd-stable@FreeBSD.ORG Thu Dec 30 08:00:18 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 29C341065673 for ; Thu, 30 Dec 2010 08:00:18 +0000 (UTC) (envelope-from kungfujesus06@gmail.com) Received: from mail-qy0-f175.google.com (mail-qy0-f175.google.com [209.85.216.175]) by mx1.freebsd.org (Postfix) with ESMTP id BEB428FC13 for ; Thu, 30 Dec 2010 08:00:17 +0000 (UTC) Received: by qyk8 with SMTP id 8so11090553qyk.13 for ; Thu, 30 Dec 2010 00:00:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:date:from:to:subject :message-id:mime-version:content-type:content-disposition:user-agent; bh=Q+o4u0ZJnv31xnhw5op/XevjYo/1/eoa21+0azkoDFc=; b=Uc1Qb05pg1DY+LJFt2Z5aoYRvVEJaoj2lz566Li9FiwOkODAgihQv9tWitwgg7muwQ ZVoTqWDY7YR3sb8uPkiV1NZV+Tj3Yq5zSpH2vQMzcUl8F6kJ/1Bw2TaLRH3PKKzjWA0u e8TpzYTXNhNrrshVKmASQtBCFbLj30I6Zhktk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=ARfFU5YKnYiPbuudR2a7z8rGCDIMdAXCAduUlIagTapduM3yi0rdP/SGiYUywcwBpn 8n23VMFIPfBfpTGNRYyM7uBu/A5fw6YH3PFlBzyVzhyqNlXR4yNINFqLMRDQgM6W0oQ0 u4f1E7orCH4+lwoTravflpn1lWFoMSMMsU/uY= Received: by 10.224.2.138 with SMTP id 10mr15043065qaj.133.1293694314258; Wed, 29 Dec 2010 23:31:54 -0800 (PST) Received: from zephyr.adamsnet ([72.49.234.31]) by mx.google.com with ESMTPS id s10sm7584602qco.47.2010.12.29.23.31.51 (version=TLSv1/SSLv3 cipher=RC4-MD5); Wed, 29 Dec 2010 23:31:52 -0800 (PST) Date: Thu, 30 Dec 2010 02:31:30 -0500 From: Adam Stylinski To: freebsd-stable@freebsd.org Message-ID: <20101230073130.GA55431@zephyr.adamsnet> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="zhXaljGHf11kAtnf" Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Subject: Re: slow ZFS on FreeBSD 8.1 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Dec 2010 08:00:18 -0000 --zhXaljGHf11kAtnf Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable I can tell you what the problem is right now, actually. ZFS performs very = poorly on low performance CPUs (i.e. your Atom N330). Try the same system = with a different CPU and you'll get a different result. It's not a lack of= bandwidth on your bus, memory, or disks, and it's not exactly the checksum= ming either (although that certainly contributes to the bottleneck), the gr= ouping of transaction groups to be flushed to the disks is what your bottle= neck is. I had an issue with some fairly poor performance with a Sempron 2= 800+ 45W TDP CPU and replacing it with an Athlon X2 did wonders. =20 --zhXaljGHf11kAtnf Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iQIcBAEBAgAGBQJNHDVRAAoJED6sRHE6Tvmn66YP/ih/lpS86FVnFaTC3GxBRGa4 y7jiv9pFI1EafWcOxulxxkTAVGH6hBCodOsZbQi+aKqJH0wVfPzRXp/TFSf4CxRH EWfIAbZsouD2bRVc3/hfsCcE7nC96DB/qArY/A9lGexW6HDpzkLd5JvBwyQLbjrr qGCcnElNH8n4AMfa5zIYW2+LoD475v5dmUff21yLNFqvdJcbZN2DivF1OAxtCsbe OjZUfIrOIifdTp0YaU33zYjM74kY/lR2oa532YJiYlExELGyMY+6P4IMsBKFj/SN 2X4JKhO5uQzLU+jWYo+WyGoL4YkAWsIz1GKIMOgteD7YpEELJ82yN3qgHxRLTsKc JG6tHsIdNwbqkyccnx2sqaHkCEeM+wpub6Xvmy5r279Z8iF9bosUSKvNeZV93fEA tv2V2VmhPqhI/DZ3v4smcomqgNgFvjjpg7jlY0boaKAK7AugAGMWZpzPzKR+mEij Ltyu6uTLyWiCE4jqdIiAQphddjyhLA4/Zl8h/bkSHqXrCqmOGRcbvRlzzoIPtqts k8yY5OkOQUSNyAAE8ygnqwUT8RzkC4f7ceIAvFuORwyg7ZBNREOgqYYXW7XO21fb 9Xq9LVc1glv/jbFw7NQqZuDVtmaRUNqA17au7ouKaJtA5uX/G4hCVX4qZGEbutaY LlRNNXnFDLM+mYxW0Cdo =0WY5 -----END PGP SIGNATURE----- --zhXaljGHf11kAtnf--