Date: Sun, 16 Apr 2000 12:03:15 -0700 From: Alfred Perlstein <bright@wintelcom.net> To: Rasmus Skaarup <rasmus@gal.dk> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: disc io - sync and async Message-ID: <20000416120315.W4381@fw.wintelcom.net> In-Reply-To: <Pine.BSF.4.21.0004161557330.63337-100000@skaarup.org>; from rasmus@gal.dk on Sun, Apr 16, 2000 at 04:02:12PM %2B0200 References: <Pine.BSF.4.21.0004161557330.63337-100000@skaarup.org>
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* Rasmus Skaarup <rasmus@gal.dk> [000416 07:30] wrote: > > Hi, > > Recently I posted a question about disc perfomance, FreeBSD vs. Linux, and > learned that Linux by default mounts the drives in async mode where > FreeBSD mounts them in sync mode. > > 2 questions arise: > > - Why is sync mode more secure? (I was told that a recovery would be less > painful if drives are mounted in sync mode - in case of a breakdown.) It's not 'sync' it's 'non-async', a 'sync' mount means that no caching is done, a 'non-async' mount means that meta-data operations are done 'sync'. Please see: http://www.ece.cmu.edu/~ganger/papers/CSE-TR-254-95/ for an explanation. > - Why does a simple 'mount' command tell me that both sync and async reads > and writes are being performed on me FreeBSD box? Because it looks cool? :) -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] "I have the heart of a child; I keep it in a jar on my desk." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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