From owner-freebsd-fs@FreeBSD.ORG Thu Jan 8 15:31:53 2009 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A9DEE1065673 for ; Thu, 8 Jan 2009 15:31:53 +0000 (UTC) (envelope-from kgysmits@gmail.com) Received: from mail-bw0-f20.google.com (mail-bw0-f20.google.com [209.85.218.20]) by mx1.freebsd.org (Postfix) with ESMTP id 03DEC8FC08 for ; Thu, 8 Jan 2009 15:31:52 +0000 (UTC) (envelope-from kgysmits@gmail.com) Received: by bwz13 with SMTP id 13so936711bwz.19 for ; Thu, 08 Jan 2009 07:31:51 -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:references; bh=CmmEPc/VkSP82hqgDfoC7Rd1cQ6Hh/5S7a3p9GpR7rw=; b=StxzaK021phQKYRI2Wk3ZGAPWvYXogXHC3TyujdRV/6dtLfR1CnsYsSvaiTePJJsc5 FJkjXQITn4ctRC27VLHgZt86M8gc8Yi3glNBfITv7AefNBv749J5eH8iqFvySNeE/nWv GFU6+jx8swzd3MXINipixmk3ZhRQlq59wXxcc= 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:references; b=NBHVFl+Vq4CAgQS5K+Nlr9pR8aHnixI19/HlIEDLqYcHoAxWi3LL9QszqwZb8cAhgV asKqJFfPiMTNsdHpMCfFBjHrmOHN9J0LKx8mF8ZGoDaxbFW2cr+I6PT7SlgrBvF0A47f yzmkMUB7a7Z+X2p2M5YvJAeQbEIL8F1/oWhtI= Received: by 10.223.108.210 with SMTP id g18mr17632468fap.38.1231428711807; Thu, 08 Jan 2009 07:31:51 -0800 (PST) Received: by 10.223.108.136 with HTTP; Thu, 8 Jan 2009 07:31:51 -0800 (PST) Message-ID: Date: Thu, 8 Jan 2009 16:31:51 +0100 From: "Koen Smits" To: "Peter Schuller" In-Reply-To: <20090108132546.GA57786@hyperion.scode.org> MIME-Version: 1.0 References: <4962A1D6.4040508@modulus.org> <20090108132546.GA57786@hyperion.scode.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-fs@freebsd.org Subject: Re: FreeBSD, SSD's and partition alignment X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Jan 2009 15:31:53 -0000 I have not tested this to an extent that I can be sure this is the way it works. Sorry. On Thu, Jan 8, 2009 at 14:25, Peter Schuller wrote: > > Note that even the Intel X25-M series seem to slow down in random write > > speed when the complete disk is filled and there are no cells left that > the > > controller knows are free. Most benchmarks out there are run on an empty > > Intel SSD. When you rerun that test several times, it'll slowly settle on > a > > much lower random write speed. > > My understanding is that the performance drop should only come from > *sustained* high write iops; i.e., when you effectively exhaust the > free space necessary to perform the writes sequentially but > temporarily. But on the other hand if you are only bursting, I was > under the impression these guys did background re-writing such that no > permanent performance drop need be expected. > > Is this not the case for the X25-M or others? > > -- > / Peter Schuller > > PGP userID: 0xE9758B7D or 'Peter Schuller ' > Key retrieval: Send an E-Mail to getpgpkey@scode.org > E-Mail: peter.schuller@infidyne.com Web: http://www.scode.org > >