I would like to run freenas on a HP P410 hardware RAID 5 4x600GB 15k SAS array and be alerted in the case of physical disk failure, however the freenas documentation says:
to prevent problems, do not enable the S.M.A.R.T. service if your disks are controlled by a RAID controller as it is the job of the controller to monitor S.M.A.R.T. and mark drives as Predictive Failure when they trip.
As the machine is installed in a lights-out data center, there's no way for the controller to alert anyone of RAID array being degraded. S.M.A.R.T. would appear to be an option - perhaps a physical disk failure would show as a high "Reallocated Sectors Count" at the array level?
Notes: Other options I have considered, but rejected are: Using a dumb HP H220 HBA with RAID-Z (<1.2TB guaranteed) or RAID 10 (1.2TB), but neither provide the capacity of RAID 5 (1.8TB), and I don't have any spare drive bays (HP DL120 G7). Also, there doesn't appear to be an HP agent for BSD. Context: I have a pair of these servers to reconfigure (main and replicated - 8 disks total) and they provide for an SQLServer and other VMs via iSCSI.
Update: I'm going down the cciss route (here's how I installed cciss on FreeNAS 9.x). Other possibility: RAID controller with out-of-band management on ethernet.