Re: degraded permanent mount option

[Andrei Borzenkov <arvidjaar@gmail.com>]

27.01.2018 13:08, Christophe Yayon пишет:
> I just tested to boot with a single drive (raid1 degraded), even with degraded option in fstab and grub, unable to boot ! The boot process stop on initramfs.
> 
> Is there a solution to boot with systemd and degraded array ?

No. It is finger pointing. Both btrfs and systemd developers say
everything is fine from their point of view.

> 
> Thanks 
> 
> --
> Christophe Yayon
> 
>> On 27 Jan 2018, at 07:48, Christophe Yayon <cyayon@nbux.org> wrote:
>>
>> I think you are right, i do not see any systemd message when degraded option is missing and have to remount manually with degraded.
>>
>> It seems it is better to use mdadm for raid and btrfs over it as i understand. Even in recent kernel ?
>> I hav me to do some bench and compare...
>>
>> Thanks
>>
>> --
>> Christophe Yayon
>>
>>> On 27 Jan 2018, at 07:43, Andrei Borzenkov <arvidjaar@gmail.com> wrote:
>>>
>>> 27.01.2018 09:40, Christophe Yayon пишет:
>>>> Hi, 
>>>>
>>>> I am using archlinux with kernel 4.14, there is btrfs module in initrd.
>>>> In fstab root is mounted via UUID. As far as I know the UUID is the same
>>>> for all devices in raid array.
>>>> The system boot with no problem with degraded and only 1/2 root device.
>>>
>>> Then your initramfs does not use systemd.
>>>
>>>> --
>>>> Christophe Yayon
>>>> cyayon-list@nbux.org
>>>>
>>>>
>>>>
>>>>>> On Sat, Jan 27, 2018, at 06:50, Andrei Borzenkov wrote:
>>>>>> 26.01.2018 17:47, Christophe Yayon пишет:
>>>>>> Hi Austin,
>>>>>>
>>>>>> Thanks for your answer. It was my opinion too as the "degraded"
>>>>>> seems to be flagged as "Mostly OK" on btrfs wiki status page. I am
>>>>>> running Archlinux with recent kernel on all my servers (because of
>>>>>> use of btrfs as my main filesystem, i need a recent kernel).> >
>>>>>> Your idea to add a separate entry in grub.cfg with
>>>>>> rootflags=degraded is attractive, i will do this...> >
>>>>>> Just a last question, i thank that it was necessary to add
>>>>>> "degraded" option in grub.cfg AND fstab to allow boot in degraded
>>>>>> mode. I am not sure that only grub.cfg is sufficient...> > Yesterday, i have done some test and boot a a system with only 1 of
>>>>>> 2 drive in my root raid1 array. No problem with systemd,>
>>>>> Are you using systemd in your initramfs (whatever
>>>>> implementation you are> using)? I just tested with dracut using systemd dracut module and it
>>>>> does not work - it hangs forever waiting for device. Of course,
>>>>> there is> no way to abort it and go into command line ...
>>>>>
>>>>> Oh, wait - what device names are you using? I'm using mount by
>>>>> UUID and> this is where the problem starts - /dev/disk/by-uuid/xxx will
>>>>> not appear> unless all devices have been seen once ...
>>>>>
>>>>> ... and it still does not work even if I change it to root=/dev/sda1
>>>>> explicitly because sda1 will *not* be announced as "present" to
>>>>> systemd> until all devices have been seen once ...
>>>>>
>>>>> So no, it does not work with systemd *in initramfs*. Absolutely.
>>>>
>>>>
>>>
>>
>> --
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>