> [ ... ] After all, btrfs would just have to discard one copy > of each chunk. [ ... ] One more thing that is not clear to me > is the replication profile of a volume. I see that balance can > convert chunks between profiles, for example from single to > raid1, but I don't see how the default profile for new chunks > can be set or quiered. [ ... ]
My impression is that the design rationale and aims for Btrfs two-level allocation (in other fields known as a "BIBOP" scheme) were not fully shared among Btrfs developers, that perhaps it could have benefited from some further reflection on its implications, and that its behaviour may have evolved "opportunistically", maybe without much worrying as to conceptual integrity. (I am trying to be euphemistic) So while I am happy with the "Rodeh" core of Btrfs (COW, sbuvolumes, checksums), the RAID-profile functionality and especially the multi-device layer is not something I find particularly to my taste. (I am trying to be euphemistic) So when it comes to allocation, RAID-profiles, multiple devices, I usually expect some random "surprising functionality". (I am trying to be euphemistic) -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
