Am 03.05.2012 20:19, schrieb Stephan Wiesand:
> On May 3, 2012, at 20:11 , Florian Philipp wrote:
> 
>> Am 03.05.2012 20:01, schrieb aurfalien:
>>> Hi all,
>>>
>>> I never really paid attention to this but a file on an NFS mount is
>>> showing 64M in size, but when copying the file to a local drive, it
>>> shows 2.5MB in size.
>>>
>>> My NFS server is hardware Raided with a volume stripe size of 128K
>>> were the volume size is 20TB, my local disk is about 500GB.
>>>
>>> Is this due to my stripe size?
>>>
>>> Nuggets are appreciated.
>>>
>>> - aurf
>>
>> Is it a sparse file? What exact command did you use to calculate the
>> file size?
> 
> A sparse file will grow when copied, not shrink.
> 

`cp` is clever enough to avoid this. Quoting the man page:
By  default,  sparse  SOURCE  files  are  detected  by  a  crude
heuristic  and the corresponding DEST file is made sparse as well.  That
is the behavior selected by --sparse=auto.

The theory was that `du` over nfs might behave more like `du
--apparent-size` locally.