Btrfs: RAID 1 on 3+ devices

linux raid btrfs

Yes, you get an extra 500 GB. Note that determining available space in btrfs remains elusive. Also: have a look at the btrfs disk usage calculator.

On your second question: You may lose some performance on your array. Naturally, your data is equally safe on both RAID configurations. When considering performance you can perhaps have a look at these benchmarks: kernel.org, phoronix.com.

Have you perhaps already tried converting to RAID 1? If so: what are your findings?

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