SMB/FTP/torrent hard disk fragmentation

So I created my unraid array recently and started using it (from my windows pc on a gigabit LAN) and I'm wondering some things about fragmentation:

1. I found that filling my array using ftp(one transfer/file at a time) will be way more convenient for me (queue, auto overwrite, auto retry, transfers/writes look faster), should I be concerned about fragmentation with ftp? should I be using smb instead to avoid fragmentation?
2. I'll be downloading torrents directly to the array via an smb share, sometimes my network speed is slow so it might take a few to several hours to download a big torrent, my torrent client has the option to "allocate and zero new files on creation", should I be using that option to prevent fragmentation? Should I be worried at all about preventing fragmentation in this case?
3. Related to the previous one, my torrent client also has the option to use sparse files instead of "allocate and zero new files on creation", would this make any difference when saving to an smb share?

Edit: I still don't know how relevant fragmentation might be for xfs but I did some quick testing with xfs_bmap, (array has new almost empty disks, the shares use "most-free" and I was using reconstruct write) and it seems that:

• SMB copy keeps the files in few pieces, 1-2 for small files and split bigger files around every 3-4GiB
• FTP copy (without writing something else at the same time) is very similar to SMB
• Torrent without preallocation will use around a piece per 1-5MiB, similar results with sparse files, sparse files seems to be working but not making a lot of difference for the amount of pieces
• Torrent with preallocation is similar to SMB or maybe even keeps the files in less pieces

Edited July 18, 20205 yr by danielocdh