Date: Sat, 2 Apr 2011 22:00:29 +0200 From: Florian Wagner <florian@wagner-flo.net> To: freebsd-stable@freebsd.org Subject: Re: Constant rebooting after power loss Message-ID: <20110402220029.243d1993@naclador.mos32.de> In-Reply-To: <201104021857.p32IvKfE024214@apollo.backplane.com> References: <87d3l6p5xv.fsf@cosmos.claresco.hr> <AANLkTi=kEyz-mKLzdV8LAf91ZhMTP8gLKs=3Eu5WD8mh@mail.gmail.com> <874o6ip0ak.fsf@cosmos.claresco.hr> <7b15d37d28f8ddac9eb81e4390231c96.HRCIM@webmail.1command.com> <AANLkTi=KEwmm1hM6Z=r_SWUAn9KhUrkTVzfF6VmqQauW@mail.gmail.com> <14c23d4bf5b47a7790cff65e70c66151.HRCIM@webmail.1command.com> <AANLkTi=6pqRwJ96Lg=603cYg_f8QUXkg8aXtbjbYpFrV@mail.gmail.com> <201104020335.p323Zp8Q018666@apollo.backplane.com> <1D1A4498-0CE0-4CE7-8DD3-6066B85C82AF@ee.ryerson.ca> <201104021857.p32IvKfE024214@apollo.backplane.com>
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--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--
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