The Fast File System
OpenBSD’s filesystem, FFS, is an improved version of the filesystem shipped with BSD 4.4. FFS is sometimes called UFS (for Unix File System), and many system utilities still use UFS.
FFS is designed to be fast, reliable, and able to handle the most common situations effectively while still supporting weird configurations. By default, OpenBSD tunes FFS for general use, but you can optimize it to fit your needs—whether you need to hold trillions of tiny files or a half dozen 30GB files. You don’t need to know much about FFS internals, but you should at least understand blocks, fragments, and inodes.
The original FFS was written in the 1980s and included hard-coded limits that were ample for the day. Filesystems ...