So, a couple of times I've been having the problem of something going wrong on raid5, drive being kicked, thus has a lower event number, re-add, during the sync a single block on one of the other drives has a read error (surprisingly common on WD20EADS 2TB drives), resync stops, I have to take down the array, ddrescue the whole read error drive to another drive, I lose that block, start up the array degraded, and then add the drive again.
It would be nice if there was an option that when re-sync:ing a drive which earlier belonged to the array, if there is a read error on another drive, just use the parity from the drive being added (in my case it's highly likely it'll be valid, and if it's not, then I haven't lost anything anyway, because the read error block is gone anyway).
Does this make sense? It would of course be nice if the md layer could see the difference between sata timeouts and UNC errors, because UNC really means something is wrong, whereas sata timeouts might be transient problem (?).
-- Mikael Abrahamsson email: swmike@xxxxxxxxx -- 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
