Date: Sun, 03 Apr 2011 11:52:52 +0100 From: Bruce Cran <bruce@cran.org.uk> To: "Marat N.Afanasyev" <amarat@ksu.ru> Cc: Marko Lerota <mlerota@claresco.hr>, freebsd-stable@freebsd.org Subject: Re: Constant rebooting after power loss Message-ID: <4D985184.5050409@cran.org.uk> In-Reply-To: <4D95F143.8080001@ksu.ru> References: <87d3l6p5xv.fsf@cosmos.claresco.hr> <AANLkTi=kEyz-mKLzdV8LAf91ZhMTP8gLKs=3Eu5WD8mh@mail.gmail.com> <874o6ip0ak.fsf@cosmos.claresco.hr> <4D95F143.8080001@ksu.ru>
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This is a cryptographically signed message in MIME format. --------------ms070907080703040202040804 Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: quoted-printable On 01/04/2011 16:37, Marat N.Afanasyev wrote: > to ensure consistency you should turn off physical drive caches, and > degrade performance significantly, sometimes up to 1000x. if this is > what you want, you may use either zfs or sync ufs. in such case you may= > be almost sure that your filesystems are consistent. but if you use > drive's cache, then without UPS you will face data loss and vanished > filesystem earlier or later I'm not sure the performance loss is so severe with modern drives=20 (attached to a decent controller). If they do tagged queuing (NCQ/TCQ) I = think a lot of the performance lost through disabling the write cache=20 can be regained through the queueing system. --=20 Bruce Cran --------------ms070907080703040202040804--
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