The guy that did this to us got 3 months jail. His argument was that we should have failed the system manually (removed the disk that he targeted with "dd"), and the raid should have magically fixed itself. Anyone think this would have worked? It was 5 hours of heavy write and deletes to the file system (ext4) and all that time the dd command where running. Later I also found this exact "test" of raid in mdadm documentation marking it as not something you should do (will fail data integriy, eg corrupt filesystem, period). /regards -----Opprinnelig melding----- Fra: Mikael Abrahamsson [mailto:swmike@xxxxxxxxx] Sendt: 19. februar 2015 15:24 Til: John Andre Taule Kopi: linux-raid@xxxxxxxxxxxxxxx Emne: Re: mdadm raid 5 one disk overwritten file system failed On Thu, 19 Feb 2015, John Andre Taule wrote: > I'm a bit surprised that overwriting anything on the physical disk > should corrupt the file system on the raid. I would think that would > be similar to a disk crashing or failing in other ways. Errr, in raid5 you have data blocks and parity blocks. WHen you overwrite one of the component drives with zeroes, you're effectively doing the same as writing 0:es to a non-raid drive every 3 $stripesize. You're zero:ing a lot of the filesystem information. > What you say that Linux might not have seen the disk as failing is > interesting. This could explain why the file system got corrupted. Correct. There is no mechanism that periodically checks the contents of the superblock and fails the drive if it's not there anymore. So the drive is never failed. -- 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
