writing large files quickly

[Erik Andreas Brandstadmoen]

Grant Edwards wrote:
> Because the filesystem code keeps track of where you are in
> that 400MB stream, and returns 0x00 anytime you're reading from
> a "hole".  The "cp" program and the "md5sum" just open the file
> and start read()ing.  The filesystem code returns 0x00 bytes
> for all of the read positions that are in the "hole", just like
> Don said:

And, this file is of course useless for FS benchmarking, since you're 
barely reading data from disk at all. You'll just be testing the FS's 
handling of sparse files. I suggest you go for one of the suggestions 
with larger block sizes. That's probably your best bet.

Regards,

Erik Brandstadmoen