On 2015-01-05 06:31, Lennart Poettering wrote:
> On Mon, 05.01.15 10:46, Harald Hoyer (harald@redhat.com) wrote:
>
>> We have BTRFS_IOC_DEVICES_READY to report, if all devices are present, so that
>> a udev rule can report ID_BTRFS_READY and SYSTEMD_READY.
>>
>> I think we need a third state here for a degraded RAID, which can be mounted,
>> but should only after a certain timeout/kernel command line params.
>>
>> We also have to rethink how to handle the udev DB update for the change of the
>> state. incomplete -> degraded -> complete
>
> I am not convinced that automatically booting degraded arrays would be
> a good idea. Instead, requiring one manual step before booting a
> degraded array sounds OK to me.
>
> Lennart
>
I can think of half a dozen use cases where it is better to 
automatically mount degraded and send a notification that this happened 
than to refuse to mount without manual intervention.