On Sun, Nov 27, 2016 at 12:16:34AM +0100, Goffredo Baroncelli wrote: > On 2016-11-26 19:54, Zygo Blaxell wrote: > > On Sat, Nov 26, 2016 at 02:12:56PM +0100, Goffredo Baroncelli wrote: > >> On 2016-11-25 05:31, Zygo Blaxell wrote: > [...] > >> > >> BTW Btrfs in RAID1 mode corrects the data even in the read case. So > > > > Have you tested this? I think you'll find that it doesn't. > > Yes I tested it; and it does the rebuild automatically. > I corrupted a disk of mirror, then I read the related file. The log says: > > [ 59.287748] BTRFS warning (device vdb): csum failed ino 257 off 0 csum 12813760 expected csum 3114703128 > [ 59.291542] BTRFS warning (device vdb): csum failed ino 257 off 0 csum 12813760 expected csum 3114703128 > [ 59.294950] BTRFS info (device vdb): read error corrected: ino 257 off 0 (dev /dev/vdb sector 2154496) > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > IIRC In case of RAID5/6 the last line is missing. However in both the > case the data returned is good; but in RAID1 the data is corrected > also on the disk. > > Where you read that the data is not rebuild automatically ? Experience? I have real disk failures all the time. Errors on RAID1 arrays persist until scrubbed. No, wait... _transid_ errors always persist until scrubbed. csum failures are rewritten in repair_io_failure. There is a comment earlier in repair_io_failure that rewrite in RAID56 is not supported yet. > In fact I was surprised that RAID5/6 behaves differently.... The difference is surprising, no matter which strategy you believe is correct. ;) > >> I am still convinced that is the RAID5/6 behavior "strange". > >> > >> BR > >> G.Baroncelli > >> -- > >> gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> > >> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 > >> > > > -- > gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> > Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 >
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