how can I reduce file fragmentation?

[rezad1393]

I have installed trasnmission on archlinux.
I have set allocation to 2 (full)
my filesystem is ext4.
when I download a big file (2-3GB) I get a lot of fragmentation by this command
find /mnt/downloads/finished -xdev -type f -exec filefrag {} +

and e4defrag shows those too (although with lower number of fragments which I don't know why)

how can I make this better (less fragments)?

[ckerr]

Using full preallocation should use fallocate64() on POSIX systems, so this should do the trick on ext4. This is the best approach that I'm aware of on modern systems. If you're still getting fragmentation, and you know of a better way to preallocate files, patches are welcomed, or if you don't want to write the patch, at least file an issue that documents a better approach than fallocate() / fallocate64() 😄