Date: Tue, 27 Jun 2006 16:15:31 +0800 From: "Leo Huang" <leo.huang.gd@gmail.com> To: "R. B. Riddick" <arne_woerner@yahoo.com> Cc: freebsd-performance@freebsd.org, leo huang <leo.huang.list@gmail.com> Subject: Re: Is the fsync() fake on FreeBSD6.1? Message-ID: <a0cd7c070606270115w4cc61d63xd7ecdd46b035b84c@mail.gmail.com> In-Reply-To: <20060627074146.7400.qmail@web30311.mail.mud.yahoo.com> References: <20060627033412.GQ10845@wantadilla.lemis.com> <20060627074146.7400.qmail@web30311.mail.mud.yahoo.com>
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hi, Arne, > 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... > :-) Good idea. But the room is noisy. I think I can not hear. :-( > I do not know, if it is possible to turn off the write cache of a SCSI disc... How can I hnow whether the write cache is turned off? 2006/6/27, R. B. Riddick <arne_woerner@yahoo.com>: > On Tuesday, 27 June 2006 at 10:18:47 +0800, leo huang wrote:me > > 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 > _______________________________________________ > freebsd-performance@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-performance > To unsubscribe, send any mail to "freebsd-performance-unsubscribe@freebsd.org" >
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