Hello, I've stumbled upon this article: http://storagemojo.com/2011/06/27/de-dup-too-much-of-good-thing/ Reportedly Sandforce SF1200 SSD controller does internally block-level data de-duplication. This effectively removes the additional protection given by writing multiple metadata copies. This technique may be used, or can be used in the future by manufactureres of other drives too. I would like to ask, if the metadata copies written to a btrfs system with enabled metadata mirroring are identical, or is there something that makes them unique on-disk, therefore preventing their de-duplication. I tried googling for the answer, but didn't net anything that would answer my question. If the metadata copies are identical, I'd like to ask if it would be possible to change this without major disruption? I know that changes to on-disk format aren't a thing made lightly, but I'd be grateful for any comments. The increase of the risk of file system corruption introduced by data de-duplication on Sandforce controllers was down-played in the vendor's reply included in the article, but still, what's the point of duplicating metadata on file system level, if storage below can remove that redundancy? Regards, Paweł -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
