From owner-freebsd-fs@FreeBSD.ORG Thu Jan 8 13:25:48 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 4F511106566B for ; Thu, 8 Jan 2009 13:25:48 +0000 (UTC) (envelope-from scode@hyperion.scode.org) Received: from hyperion.scode.org (cl-1361.ams-04.nl.sixxs.net [IPv6:2001:960:2:550::2]) by mx1.freebsd.org (Postfix) with ESMTP id 10A808FC16 for ; Thu, 8 Jan 2009 13:25:47 +0000 (UTC) (envelope-from scode@hyperion.scode.org) Received: by hyperion.scode.org (Postfix, from userid 1001) id E993123C443; Thu, 8 Jan 2009 14:25:46 +0100 (CET) Date: Thu, 8 Jan 2009 14:25:46 +0100 From: Peter Schuller To: Koen Smits Message-ID: <20090108132546.GA57786@hyperion.scode.org> References: <4962A1D6.4040508@modulus.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="BOKacYhQ+x31HxR3" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) 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 13:25:48 -0000 --BOKacYhQ+x31HxR3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > 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 t= he > 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? --=20 / 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 --BOKacYhQ+x31HxR3 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkll/tkACgkQDNor2+l1i33DAgCfe77a9WZOkQa/NdI1MQY7Bgr8 PMwAn1Ku8iJunO4nlntHKJwQNPgl16JM =CB7q -----END PGP SIGNATURE----- --BOKacYhQ+x31HxR3--