Thank you all for your feedback. I was afraid that I had to move data around, well, I'll do then :) It'll just be quite long and boring… @Robert: Even if copying to another disk or box would be speedier, I'm talking about moving twice ~90TB here, so… @Les: I've had enough disk failures to be sure fault-tolerance already works like a charm ^^ @Natxo: I'll do it keeping boxes up, disk per disk (fs lags a bit when automatic replication kicks in due to 12/16/24/36 disks disappearing from the pool like a single man :D) Thanks again !