aeobd is a tool I wrote to help make a bootable replica of an OpenBSD installation, thus reducing downtime to a couple of minutes. It operates at file level instead of doing a bitwise copy, and can be quite fast after the initial replication. It is meant for hardware on which solutions involving the /altroot facility in daily(8) are not pratical, typically laptops with only one hard disk but the ability to boot from removable hard disks.
It works with i386 and amd64 systems.
NOTE: this is not an official OpenBSD tool. Nobody over there knows about it.
Download it from here.