Date: Tue, 27 Jun 2006 00:41:46 -0700 (PDT) From: "R. B. Riddick" <arne_woerner@yahoo.com> To: leo huang <leo.huang.list@gmail.com> Cc: freebsd-performance@freebsd.org Subject: Re: Is the fsync() fake on FreeBSD6.1? Message-ID: <20060627074146.7400.qmail@web30311.mail.mud.yahoo.com> In-Reply-To: <20060627033412.GQ10845@wantadilla.lemis.com>
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On Tuesday, 27 June 2006 at 10:18:47 +0800, leo huang wrote: > And how I can confirm this? > You could do this test: 1. write some data with dd if=/dev/zero of=/tmp/a bs=1m count=100 2. then fsync /tmp/a 3. then listen to the hard disc 4. repeat it until u r sure, if the hard disc reacts on the fsync command... :-) I do not know, if it is possible to turn off the write cache of a SCSI disc... On the freebsd-geom@ list was something about a new feature (the BIO_FLUSH request), that can flush the write caches of hard discs. But it just works for ata and amr discs currently... See: http://docs.freebsd.org/cgi/getmsg.cgi?fetch=3624+0+archive/2006/freebsd-geom/20060625.freebsd-geom -Arne __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
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