Date: Sat, 3 Mar 2007 18:22:39 -0500 From: Jerry McAllister <jerrymc@msu.edu> To: Christian Baer <christian.baer@uni-dortmund.de> Cc: freebsd-questions@freebsd.org Subject: Re: defrag Message-ID: <20070303232239.GA96768@gizmo.acns.msu.edu> In-Reply-To: <esbukq$30u3$5@nermal.rz1.convenimus.net> References: <539c60b90703010849x33dd4bbbt8f6ca6aa0c8e83a0@mail.gmail.com> <20070301192109.A24369@chylonia.3miasto.net> <20070302085100.125cf488@localhost> <20070301221738.GA86154@gizmo.acns.msu.edu> <20070301223905.GA86318@gizmo.acns.msu.edu> <esbukq$30u3$5@nermal.rz1.convenimus.net>
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On Sat, Mar 03, 2007 at 02:53:30PM +0100, Christian Baer wrote: > On Thu, 1 Mar 2007 17:39:05 -0500 Jerry McAllister wrote: > > >> Well, it would do some, but for the greatest effect, you would need: > >> dump + rm -rf * + restore > >> That would get it all. > > > Of course, I should have re-emphasized that this is not needed. > > You will not improve performance. Its only value might be to exercise > > every used file block on the filesystem to make sure it is still > > readable. And for that you don't need to nuke and rewrite things. > > You could of try changing the above command into 'rm -rfP *'. That would > make sure everything on your file system is still readable. And it would > give you a lot of time to think about it. :-) > > > Just doing the backup (which you should do anyway) will read up all > > used file space (except what you might have marked as nodump). > > Actually, that way you won't get every sector on the drive - not unless > the drive is full to the brim anyway. Note that I did say all of the _used_ space - eg actual files. > > If you really just want to check the drive, use > smartctl -t long /dev/whatever > > You could also try > dd if=/dev/whatever of=/dev/null bs=1m > > The idea with the backup isn't a bad one either. Cause if your drive > goes up in flames, you don't really care. You still have your data. Yup, just what I was sort of pointing out. ////jerry > > Regards > Chris > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org"
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