There is a Linux daemon that will alert the system administrator if there are problems with any of the disks in the array. The ICP-Vortex is only supported as of 2.0.33, but the company appears very dedicated to supporting Linux. The SCSI to SCSI solutions vary wildly. There are solutions from many companies including Mylex, CMD, and others. These solutions are usually external or requiring a full height slot in the case for the controller.
Some models have one or the other and some have both.
The biggest drawback to these types of controllers is that they are usually on the expensive side. The CMD controllers are the only ones I know of that offer Linux software to do the administration. They have several models available including one that is a dual redundant hot swappable controller. CMD controllers can also be upgraded to multiple channels with expansion cards. Many companies produce SCSI to SCSI solutions.