On Tue, Oct 13, 2015 at 06:29:41PM +0800, Zhao Lei wrote: > Current code don't support dup profile in single device, except it > is in mixed mode, because following reason: > 1: In some ssd with deduplication function, it have no effect. > 2: For a physical device, it the entire disk broken, -d dup can > not help. > 3: Half performance comparing with single profile. > 4: We have a workaround: Create multi-partition in single device, > and btefs will treat them as multi device. While the above makes sense is true, I'm not sure that DUP was disabled for these reasons. I'm sure that I read a comment from Chris that dup for data is intentionally disabled because this would lead to corruption, the code for DUP for metadata would not work for data. And I can't find the comment, but the doubt is there. So unless I find it or get otherwise convicend that it's ok, I won't merge the patch. I hope you understand that. What I remember from the comment is that "it's slightly offset that would lead to corruption". -- 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
