From the article: 'And against the demand of some partners, we are still refusing to support “Automatic Defragmentation”, “In-band Deduplication” and higher RAI

From the article: 'And against the demand of some partners, we are still refusing to support “Automatic Defragmentation”, “In-band Deduplication” and higher RAID levels, because the quality of these options is not where it ought to be.' I've only used btrfs on single disk systems.