As I understand it, the event count on all devices in an array should be the same. If they're a little bit different it doesn't matter too much. My question is how much does it matter? Let's say I've got a raid-5 and suddenly realise that one of the drives has failed and been kicked from the array. What happens if I force a reassemble? Or do a --re-add? I don't actually have a clue, and if I'm updating the wiki I need to know. What I would HOPE happens, is that the raid code fires off an integrity scan, reading each stripe, and updating the re-added drive if it's out-of-date. Is this what the bitmap enables? So the raid code can work out what changes have been made since the drive has been booted? Or does forced re-adding risk damaging the data because the raid code can't tell what is out-of-date and what is current on the re-added drive? Basically, what I'm trying to get at, is that if there's one disk missing in a raid5, is a user better off just adding a new drive and rebuilding the array (risking a failure in another drive), or are they better off trying to add the failed drive back in, and then doing a --replace. And I guess the same logic applies with raid6. Cheers, Wol -- 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
