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Re: Identifying sparse files using getattrlist()
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Re: Identifying sparse files using getattrlist()



When I use
# mkfile -nv 4g sparse
on a 7GB Apple_UFS partition

df -k gives me this :

#df -k
Filesystem   1024-blocks Used Available Capacity  Mounted on
/dev/disk2s3     7390568   40   7021000     1%    /Volumes/UFSVolume

This indicates that the file created is sparse since it shows Capacity as 1%

On Tue, Nov 3, 2009 at 4:27 PM, Alastair Houghton
<email@hidden> wrote:
> On 2 Nov 2009, at 13:37, rohan a wrote:
>
>> I am trying to identify if a particular file is a sparse file using
>> getattrlist()
>>
>> I am using this :     attrList.fileattr    = ATTR_FILE_TOTALSIZE |
>> ATTR_FILE_ALLOCSIZE;
>>
>> According to the man page if  ATTR_FILE_ALLOCSIZE <
>> ATTR_FILE_TOTALSIZE the file is a sparse file.
>>
>> I created the sparse file using dd
>> #dd if=/dev/zero of=sparse-file bs=1 count=0 seek=3g
>>
>> However, both AllocSize and TotalSize are returning the same size
>> while actually AllocSize < TotalSize
>>
>> I am using UFS
>
> Does Apple UFS even support sparse files?  Remember, UFS is a name used by a
> fair number of totally different and usually incompatible filesystems.  I
> haven't really ever bothered investigating exactly what Apple's UFS can and
> can't do... indeed, I've always had the impression that it was only really
> present for the benefit of old-time NeXT users who might have compatible
> filesystems floating around already.
>
> Kind regards,
>
> Alastair.
>
> --
> http://alastairs-place.net
>
>
>
>
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References: 
 >Identifying sparse files using getattrlist() (From: rohan a <email@hidden>)
 >Re: Identifying sparse files using getattrlist() (From: Alastair Houghton <email@hidden>)



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