On Thu, Oct 27, 2016 at 12:31:58AM +0200, Vojtech Pavlik wrote: > In case you're using mdraid for the RAID part on a reasonably recent > Linux kernel, there is no write hole. Linux mdraid implements barriers > properly even on RAID5, at the cost of performance - mdraid waits for a > barrier to complete on all drives before submitting more i/o. That's not what the raid 5 hole is. The raid 5 hole comes from the fact that it's not possible to update the p/q blocks atomically with the data blocks, thus there is a point in time when they are _inconsistent_ with the rest of the stripe, and if used will lead to reconstructing incorrect data. There's no way to fix this with just flushes. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
