Hello boys, I am running some RAID6 arrays in degraded mode, one with left-symmetry layout and one with left-symmetry-6 layout. I am experiencing (potentially strange) behavior that degrades performance of both arrays. When I am writing sequentially a lot of data to healthy RAID5 array, it also reads internally a bit of data. I have data on arrays, so I only write through the filesystem. So I am not sure what causing the reads, if writing through filesystem potentially causes skipping and not writing whole stripes or sometimes timing causes that the whole stripe is not written at the same time. But anyway there is only a small ratio of reads and the performance is almost OK. I cant test it with full healthy RAID6 array, because I dont have any at the moment. But when I write sequentially to RAID6 without one drive (again through filesystem) I get almost exactly the same amount of internal reads as writes. Is it by design and is this expected behaviour? Why does it behave like this? It should behave exactly like healthy RAID5, it should detect the writing of whole stripe and should not read (almost) anything. Thanks. Patrik -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
