On Fri, Nov 13, 2015 at 10:11:37PM +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. > > Instead of refuse -d dup, we have a better choise: > Give user a chance to select, and output a warning to notice above > problem. > > Test: [...] Thanks. > + warning_on(!mixed && (data_profile & BTRFS_BLOCK_GROUP_DUP) && ssd, > + "DUP have no effect if your SSD have deduplication function"); This seems too specific, I suggest to say something generic that duplicate does not necessrily be stored twice and point to the manual page where we can be detailed as needed. Patch will be added to devel branch soon. -- 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
