Mystery is solved: "In most cases, removing all filenames associated with an inode will reduce the reference counter to zero, but it turns out you can also hav

Mystery is solved: "In most cases, removing all filenames associated with an inode will reduce the reference counter to zero, but it turns out you can also have a file referred to by zero file names, but with a non-zero reference counter, which is what was happening here. The file had a non-zero reference count because it was memory mapped, even though no filename pointed to it. The reference counter doesn’t decrement until you un-map the memory." At 1st glance this may appear weird, but not when thinking about it. It means diskspace that isn't referred to by a filename, but which is allocated / used in some way ("reserved" comes to mind). On the other hand, it does seem weird one could create memory mapped diskspace without somehow assigning a filename to that? Or delete memory mapped file, but have the memory mapping + corresponding diskspace remain? More logical -imho- would be delete mm file -> corresponding RAM either freed, or non-file mapped. Appearently Java version used (specifically: its GC) isn't good at handling / cleaning up in situations like this.