Best hardware to mirror IDE drives under FreeBSD?

[Brett Glass]

I need to set up a FreeBSD server with two or more sets of
mirrored drives. What is the best controller to use for this
purpose? Note that I don't need striping or other RAID
functions -- just mirroring, hopefully with hot swap capability.
A system that could re-mirror a replacement drive with minimal
impact on performance would be ideal.

--Brett Glass