Hi Neil, can you pls give some details on that commit. As far as I understand, this change attempts to protect from split-brain, most typical to RAID1 (but also, e.g., to 4-drive RAID6) , where part of a mirrored set was assembled independently. The code first selects "most_recent" based on event count (as usual). Then it applies the map check to all those devices that are not "most_recent", and might kick them out, if it detects split-brain. However, when there is such split-brain, and parts of mirrored sets are assembled independently, the highest event count does not really tell us which part of the mirrored set is "more up-to-date". This is because event count is not tied to any hard clock or something like that. So there is really no way to tell what part of the mirrored set will be picked up here (WRT to user activity on the separate mirrored sets). What I am trying to say, I guess: don't you think that in such case, it would be better to warn the user and abort, and not pick (more or less) arbitrary part of the set? Or, in other words:) might you reconsider looking at some ideas for split-brain protection I pitched some time ago?:)) Thanks! Alex. -- 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
