From owner-freebsd-stable@FreeBSD.ORG Sat Apr 2 20:18:46 2011 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 8D652106564A for ; Sat, 2 Apr 2011 20:18:46 +0000 (UTC) (envelope-from florian@wagner-flo.net) Received: from umbracor.wagner-flo.net (umbracor.wagner-flo.net [213.165.81.202]) by mx1.freebsd.org (Postfix) with ESMTP id 49D6C8FC12 for ; Sat, 2 Apr 2011 20:18:46 +0000 (UTC) Received: from naclador.mos32.de (ppp-93-104-1-42.dynamic.mnet-online.de [93.104.1.42]) by umbracor.wagner-flo.net (Postfix) with ESMTPSA id E1D5E3C058F6 for ; Sat, 2 Apr 2011 22:00:30 +0200 (CEST) Date: Sat, 2 Apr 2011 22:00:29 +0200 From: Florian Wagner To: freebsd-stable@freebsd.org Message-ID: <20110402220029.243d1993@naclador.mos32.de> In-Reply-To: <201104021857.p32IvKfE024214@apollo.backplane.com> References: <87d3l6p5xv.fsf@cosmos.claresco.hr> <874o6ip0ak.fsf@cosmos.claresco.hr> <7b15d37d28f8ddac9eb81e4390231c96.HRCIM@webmail.1command.com> <14c23d4bf5b47a7790cff65e70c66151.HRCIM@webmail.1command.com> <201104020335.p323Zp8Q018666@apollo.backplane.com> <1D1A4498-0CE0-4CE7-8DD3-6066B85C82AF@ee.ryerson.ca> <201104021857.p32IvKfE024214@apollo.backplane.com> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.22.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/Y3.lLhNQ=WTn+5cSOhvRVAH"; protocol="application/pgp-signature" Subject: Re: Constant rebooting after power loss 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: Sat, 02 Apr 2011 20:18:46 -0000 --Sig_/Y3.lLhNQ=WTn+5cSOhvRVAH Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable > I am unaware of *ANY* mainstream hard drive or SSD made in the > last 10 years which ignores the disk flush command. In previous > decades HD vendors played games with caching all the time but there > are fewer HD vendors now and they all compete heavily with each > other... they don't play those games any more for fear of losing > their reputation. There is very little vendor loyalty in the hard > drive business. >=20 > When it comes to SSDs there are all sorts of fringe vendors, and I > certainly would not trust any of those, but if you stick to > well known vendors like Intel or OCZ it will work. Look for who's > chipsets are under the hood more than for whos name is slapped > onto the SSD and get as close to the source as you can. As far as my knowledges goes all mainstream non-enterprise SSD do not obey the cache flush command at all. The question for a recommended SSD for ZIL-use regularly comes up on the zfs-discuss mailing list and the general consensus seems that no non-enterprise SSD can really be recommended because of this issue. The only publicly available SSDs which do not exhibit this are those with a Sandforce enterprise controller (SF-1500 if my memory serves me correctly) and a capacitor (OCZ sells such models) and the Intel X25-E with it's write cache turned off (also resulting in horrible write performance all around). I've had the chance to verify this with a Corsair Force SSD with the SF-1200 controller. It consistently "lost" about 1,2 to 1,5 MB of data which it claimed to have committed to disk.=20 Regards Florian --Sig_/Y3.lLhNQ=WTn+5cSOhvRVAH Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) iEYEARECAAYFAk2XgF0ACgkQLvW/2gp2pPymlACffemZgtR4pFVoMUSEKuWbLD66 3D8AoIHflFfAQK8nmXb5fCWvR1Hxt8xF =d/4u -----END PGP SIGNATURE----- --Sig_/Y3.lLhNQ=WTn+5cSOhvRVAH--