Create new files as sparse on NT systems. (2nd try)

Max Bowsher
Mon Feb 17 18:03:00 GMT 2003

Vaclav Haisman wrote:
>> Is it wise to set *all* new files to sparse? Surely if this was
>> actually advantageous, Windows would do it anyway? From MSDN: "Note
>> It is up to the application to maintain sparseness by writing zeros
>> with FSCTL_SET_ZERO_DATA." I.e., this will gain nothing unless the
>> application knows about sparse-ness, in which case, it should
>> explicitly specify that the file should be sparse. So, all this
>> patch will do is to force Windows to examine more metadata for every
>> file read. This seems *extremely undesirable*.
>> Max.
> As I have written in my previous emails in FreeBSD and SunOS all
> files are sparse if underlying file system supports it. I doubt
> Windows is significantly slower/faster in inspecting file system
> metadata than either of these OSes,

That's nice. Did you read the bit above where I quoted MSDN? Merely setting
the file as sparse will NOT SAVE SPACE on Windows. So, no space gain, and a
performance penalty of untested magnitude. I see only disadvantages.


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