> Ok... how does that alter the fact that we should not be automatically > adding devices to arrays that have been explicitly removed?
Not at all, we agree that explicitly --remove(ing) a device is a good way to tell mdadm --incremental (its hotplug control mechanism) not to re-add automatically. Personally I could even agree that it might be OK for "mdadm --add" not to require --force, but you don't seem to agree that "mdadm --incremental" really needs to be able to auto-re-add (not manually removed but missing) devices, in a safe manner. >> be an admin available. And if there is an admin, and he allways has >> to re- add removed members manually, how does he notice if a user >> made conflicting changes? > > He will notice when he sees that the array is degraded and refusing to > use one of the disks. If I read your proposal correctly, running an array degraded would always also "remove" the missing disk. This would imply to * break all the auto-re-add later feature of mdadm --incremental (it also sports auto-read-only-until-write), even though it is perfectly safe in the majority of cases (no conflicts). * force users/admins to *allways* re-add manually after an array is running degraded (this is not supporting hot-plugging, rather the contrary) * make the perfectly safe re-addition of an outdated member device ( i.e. older backup) look indistinguishable from re-adding a member with conflicting changes (with data-loss!). The admin (*allways* forced to --add manually) can not notice when the operation will cause data loss. >> I am not sure if we are considering the valid use case of auto >> re-adding members enough here, yet. (Even if auto-adding just >> "missing" and not "removed" members.) I.e. the case of >> docking-stations / external backup drives. > > I'm not quite sure what you mean here. A device that is removed should > never be automatically added when detected. Please check https://wiki.ubuntu.com/HotplugRaid for example, and understand the need of a hot-plugging scheme that supports safe auto-re-adding. If you manually --remove a member it should not get auto-re-added. If a member is only missing for a while, yes the array should keep running as well as be run degraded upon boot (as long as no conflicting changes were made). -- array with conflicting changes is assembled with data corruption/silent loss https://bugs.launchpad.net/bugs/557429 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
