From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.saout.de ([127.0.0.1]) by localhost (mail.saout.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id g8fJSPmpsLPb for ; Mon, 23 Jul 2012 19:37:58 +0200 (CEST) Received: from turboconrad.planet-school.de (mail.planet-school.de [194.116.187.5]) by mail.saout.de (Postfix) with ESMTP for ; Mon, 23 Jul 2012 19:37:57 +0200 (CEST) Received: from turboconrad.planet-school.de (srv004.service.ps-server.net [194.116.186.79]) by turboconrad.planet-school.de (Postfix) with ESMTP id 69E94B6A009 for ; Mon, 23 Jul 2012 19:28:12 +0200 (CEST) Received: from [192.168.1.103] (HSI-KBW-46-223-75-209.hsi.kabel-badenwuerttemberg.de [46.223.75.209]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: postmaster@andregall.de) by turboconrad.planet-school.de (Postfix) with ESMTPSA id 53A8CB6A002 for ; Mon, 23 Jul 2012 19:28:12 +0200 (CEST) Message-ID: <500D8993.7030802@andregall.de> Date: Mon, 23 Jul 2012 19:27:47 +0200 From: =?ISO-8859-1?Q?Andr=E9_Gall?= MIME-Version: 1.0 References: <20120722190757.GB10089@merlins.org> <20120722202213.GA7306@fancy-poultry.org> <20120722190757.GB10089@merlins.org> <1342986452.26887.3.camel@scapa> <20120722203929.GB3925@merlins.org> <20120722214757.GA16793@tansi.org> <20120723062850.GA6931@merlins.org> <20120723081407.GA872@tansi.org> <500D2B8E.3000908@redhat.com> <1343041780.26887.19.camel@scapa> <500D3776.2000307@redhat.com> In-Reply-To: <500D3776.2000307@redhat.com> Content-Type: text/plain; charset="iso-8859-1"; format="flowed" Content-Transfer-Encoding: quoted-printable Subject: Re: [dm-crypt] aes-xts-plain with aes_x86_64 makes my SSD 5x slower than my encrypted HD List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de I remember a test which I conducted after I received my Intel SDD 510=20 120 GB about 1 year ago. I don't remember all the details, but the=20 essence was that write speed decreased dramatically if the write process=20 wasn't aligned. I did: dd if=3D/dev/zero of=3D/dev/sda bs=3D4k I got around 400 Mb/sec, which was expected. But when I did: dd if=3D/dev/zero of=3D/dev/sda bs=3D5k I got only around 40 Mb/sec When you write in 5k blocks, the SSD has to do a lot of overhead because=20 of the Read-Modify-Write operations. I guess this might also be the case=20 if you write in 4k blocks, but don't align them to the SSD's "native"=20 blocks. So I would check for any misalignment. Regards, Andr=E9