I have a low-power VIA x86 PC with one SATA port. I want to backup special files (ie: /var) from the SATA drive on this port onto a USB flash disk, but I don't want a RAID1 or fully-synchronous solution for performance reasons.
It is acceptable that data isn't entirely 100% durable/reliable, but I am looking for something more elegant than rsync-ing every 5minutes in crontab.