What are the issues regarding large drives with OpenBSD?
OpenBSD supports both FFS and FFS2 (also known as UFS and UFS2) file systems. FFS is the historic OpenBSD file system, FFS2 is new as of 4.3. Before looking at the limits of each system, we need to look at some more general system limits. Of course, the ability of file system and the abilities of particular hardware are two different things. A new 250G IDE hard disk may have issues on older (pre >137G standards) interfaces (though for the most part, they work just fine), and some very old SCSI adapters have been seen to have problems with more modern drives, and some older BIOSs will hang when they encounter a modern sized hard disk. You must respect the abilities of your hardware, of course.