On 2006-01-27, Erik Andreas Brandstadmoen <[EMAIL PROTECTED]> wrote: > 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.
Quite right. Copying such a sparse file is probably only really testing the write performance of the filesystem containing the destination file. > You'll just be testing the FS's handling of sparse files. Which may be a useful thing to know, but I rather doubt it. > I suggest you go for one of the suggestions with larger block > sizes. That's probably your best bet. -- Grant Edwards grante Yow! Now I'm concentrating at on a specific tank battle visi.com toward the end of World War II! -- http://mail.python.org/mailman/listinfo/python-list