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Re: SPARSE files considered harmful - please revert
On Mon, May 19, 2003 at 12:46:19PM -0400, Bill C. Riemers wrote:
>> Um? By my understanding, making a file sparse can never be dangerous. It
>> cause sub-optimal performance, but code reading the file doesn't have to
>> aware of anything special - the OS takes care of it.
>I remember there use to be a warning the man page that file system holes can
>cause seek offsets to be wrong for programs that do seek's across or into
>hole boundries. The original Linux code only handled when code was loaded
>as a result of an mmap which happens for exec's and dlopen. It could be by
>now these restrictions have been eliminated. I notice the latest GNU cp
>info page lists sparse files a filesystem capacity not a kernel capability,
>and the logic for --sparse=auto simply copies a file as-is, nothing smart
>like checking for the execution bit.
>I looked through the NTFS document on MSDN. It seems at least for NTFS
>there is no restriction on what types of files can be sparse. Of course, if
>you make files sparse that are going to be accessed with RW operations, you
>are going to fragment the file.
I think you need to read the documentation a little more closely. Either that
or provide references to the parts of the documentation that says that normal
RW operations would fragment a sparse file.
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