It'd be interesting to see a real world test of this. I'm not sure how large the sample variation is with these units, but if you're actually hitting the write

It'd be interesting to see a real world test of this. I'm not sure how large the sample variation is with these units, but if you're actually hitting the write limits of your disks I don't think mirroring is going to be the most effective solution - as both disks are likely to start failing at roughly the same sort of time. Mirroring is really useful with spinning rust, where failures are (more or less) unpredictable and you need a spare to use while the first is replaced. I wonder if there's a better solution when the failure of the drive is more predictable that avoids having a second unit sitting there all the time - especially for applications where the data isn't absolutely critical.