> desperately needs defrag, which it does not have OK, this is interesting to me, because it takes me back to the 1990s, when Windows users coming from Windows

> desperately needs defrag, which it does not have OK, this is interesting to me, because it takes me back to the 1990s, when Windows users coming from Windows 95 (who were also Windows 3.11 and MS-DOS users prior to that) would come to Linux and, having been of the Power User variety back in Windows-land, would ask "How do I defrag my disks?" Of course, by then Linux was on ext2 or similar, so the response was "Real filesystems don't need defragging. The kernel keeps track of free space automatically. Don't worry about it." And, generally, it worked pretty well. (Source: I like to fill disks. I've never seen a big slowdown even unto the point of "no space left on medium" errors.) So why does ZFS, a Thoroughly Modern Filesystem by any account, need defragging?