small du(1) question
Alexander Best
arundel at freebsd.org
Wed Oct 19 20:47:54 UTC 2011
On Wed Oct 19 11, Alexander Best wrote:
> On Wed Oct 19 11, Chuck Swiger wrote:
> > On Oct 19, 2011, at 12:34 PM, Alexander Best wrote:
> > > the du(1) man page states the following:
> > >
> > > "
> > > -B blocksize
> > > Calculate block counts in blocksize byte blocks. This is differ-
> > > ent from the -k, -m options or setting BLOCKSIZE and gives an
> > > estimate of how much space the examined file hierarchy would
> > > require on a filesystem with the given blocksize. Unless in -A
> > > mode, blocksize is rounded up to the next multiple of 512.
> > > "
> > >
> > > is this a doc bug, or does du(1) really always assume that every filesystem's
> > > blocksize == 512?
> >
> > The default blocksize is 512 bytes.
> >
> > The -B option flag lets you tell du to assume a different filesystem blocksize.
>
> so when running freebsd on a hdd with a blocksize of 4k, a simple 'du -h' will
> always display incorrect results, unless '-B 4096' was also specified? isn't
> there a way to automatically query the blocksize of the underlying device,
> instead of always asuming the blocksize is 512 byte?
...also: since -A is supposed to take the actual file size into account and not
the blocksize of the underlying filesystem, shouldn't the output of
'du -A -B4096' and 'du -A' be the same? just tested this on freebsd 7 and
freebsd 10 and the outputs differ.
cheers.
alex
>
> cheers.
> alex
>
> >
> > Regards,
> > --
> > -Chuck
> >
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