On 14.12.2012 13:57, Ric Wheeler wrote: > On 12/14/2012 11:19 AM, Matthias Schniedermeyer wrote: > >>>>http://xfs.org/index.php/XFS_FAQ#Q:_What_information_should_I_include_when_reporting_a_problem.3F > >>>> > >>>>Basically, you have an IO error situation, and you have dm-crypt > >>>>in-between buffering an unknown about of changes. In my experience, > >>>>data loss eventsi are rarely filesystem problems when USB drives or > >>>>dm-crypt is involved... > >>>I don't know the inner workings auf dm-*, but shouldn't it behave > >>>transparent and rely on the block-layer for buffering. > >>I think that's partly why Dave asked you to test it, to check > >>that theory ;) > >To test that theory. > > > >Technically this is an other machine than the original but i tried to > >recreate as much from the original cirumstances as possible. > >Kernel is 3.6.7 > > > >First i recreated the circumstances. > >I plugged a HDD i'm throwing out into the enclosure that was the most > >problematic, created the dm-crypt-layer & filesystem as reported and > >started copying. > > > >In all testes i didn't supply any mount-options! > > > >1) > >After a few minutes i "emulated" the problem by unplugging the cable. > >At that point about 40 files were copied, but only 25 where there after > >i replugged the cable. > > Just a note - depending on the drive and its firmware, unplugging a > cable is *not* the same as a power loss since the firmware detects > the loss of link and immediately writes back any volatile cache data > to platter (and it has power, so that is easy for it to do :)). > > You really should drop power to the enclosure to get a "mean" test :) The Power loss case is irrelevant for me. I know what i can expect for a power-loss, all my drives have 'write-cache on' and (up to) 64MB of cache. As a disabled write cache isn't an option (performance sucks) the ensuing data-loss would be expected and there are procedures in place to prevent any permanent data-losses (Except for the right 2 discs dying at the same time). -- Matthias _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
