On Aug 19, 2012, at 4:19 PM, NeilBrown wrote: > On Sun, 19 Aug 2012 12:12:38 -0600 Chris Murphy <lists@xxxxxxxxxxxxxxxxx> > wrote: > >> On Aug 19, 2012, at 3:47 AM, Mikael Abrahamsson wrote: >>> If I remember correctly from what has been described here before, a read error will cause a re-write with information created from parity >> >> That's the thing I'd like to get a definitive answer one. If only it were easy to simulate bad sectors in VM's I could just test it! > > If only it were easy to read the documentation, and if only the documentation > were sufficiently complete..... > > % man 4 md > > search for 'read error' The well deserved and diplomatic variant of RTFM. So the summary is: a write error on RAID 1456 causes md to mark the device as faulty. A read error (with recent kernels) causes correct data to overwrite the bad block *and* re-read, and if either write or re-read fails, the device is marked faulty. Very cool. BTW, there's a lot of detail nuggets in man md that I'm not finding documented anywhere else. Nor have I found in other documentation a reference to man md until now. Chris Murphy-- 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
