It probably uses a combination of the SMART data and actual failures when reading/writing data to the drives. Verify should be the same as a scrub. The process involves reading the data, calculating the parity, and verifying it matches the written parity. If a memory bit flip occurred the parity would not match. If you were rebuilding from a failed drive that stripe of data would be corrupted. You will hard pressed to find a server without ECC memory.
I wouldn't go buying a new system just for ECC memory. When I mentioned horror stories I should have put that in the paragraph above. Most commonly you see large arrays with only one parity drive where another drive failed during rebuild. Second you will see multiple drive failures from running an array for years with no scrubs. Lastly is ECC memory. The chance is low that a bit flip will occur. I have 8GB ECC memory and no memory errors have been detected in the 6 years it has been running. I have another box with 24GB ECC memory with no issues either. At work I've seen one server have an ECC memory error where we ended up replacing the memory. However if you do decide to split the system into separate boxes I would opt for ECC memory.
You mentioned you are only seeing 160MB/s with FlexRAID. Gigabit ethernet provides 100MB/s which is plenty fast for streaming video. If speed is your thing I would look at a solution besides FlexRAID. I am seeing 190MB/s reading data from 4 drives. With the number of drives you have it should easily hit 400-800MB/s.
I wouldn't go buying a new system just for ECC memory. When I mentioned horror stories I should have put that in the paragraph above. Most commonly you see large arrays with only one parity drive where another drive failed during rebuild. Second you will see multiple drive failures from running an array for years with no scrubs. Lastly is ECC memory. The chance is low that a bit flip will occur. I have 8GB ECC memory and no memory errors have been detected in the 6 years it has been running. I have another box with 24GB ECC memory with no issues either. At work I've seen one server have an ECC memory error where we ended up replacing the memory. However if you do decide to split the system into separate boxes I would opt for ECC memory.
You mentioned you are only seeing 160MB/s with FlexRAID. Gigabit ethernet provides 100MB/s which is plenty fast for streaming video. If speed is your thing I would look at a solution besides FlexRAID. I am seeing 190MB/s reading data from 4 drives. With the number of drives you have it should easily hit 400-800MB/s.