Date: Tue, 29 Jul 2003 17:02:15 +0100 From: Bruce Cran <bruce@cran.org.uk> To: Bogdan TARU <bgd@icomag.de> Cc: freebsd-hackers@freebsd.org Subject: Re: file size different from ls to du Message-ID: <20030729160215.GA3822@buffy.brucec.backnet> In-Reply-To: <20030729172615.N13255-100000@fw.office.icom> References: <200307291524.h6TFO3J06998@revolt.poohsticks.org> <20030729172615.N13255-100000@fw.office.icom>
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On Tue, Jul 29, 2003 at 05:27:14PM +0200, Bogdan TARU wrote: > > Hi Drew, > > I have tried to create some files of myself, with 'spaces' in them > (holes?), but they don't act like this. So could you please explain what > 'sparse' means, and the 'trick' to create them? > Try using the 'truncate' utility: truncate -s 102400G onehundred_terabytes This will create a file which looks like it's 100TB though 'ls', but which only uses 64KB in the directory usage via 'du'. Generally, creating a file, seeking past the end of the file then writing something, will create a 'sparse' file. This, when read, will appear to contain zeros for all entries past the previous end of file, to the entry which was written to. -- Bruce Cran
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