So I just found the command
filefrag. I thought I'd see if any of my files are fragmented. I have quite a few large files, [500MB/+] and every single one I've tried has 5 to 42 extents found.
What's going on? I have EXT4, and I have 185G of 515G free [63% used].
I thought EXT3 and EXT4 didn't fragment files [unless absolutely necessary]. I did restore all my files actually, from a NTFS partition [My ext. hdd is NTFS. I've thought about formatting it to EXT, but it's 0.5TB and would take a long time to recopy my files] after I switched to a new laptop a week ago.
So how do I defragment these files, and why are they fragmented?