Re: Unexpected raid1 behaviour

[Tomasz Pala <gotar@polanet.pl>]

On Tue, Dec 19, 2017 at 12:35:20 -0700, Chris Murphy wrote:

> with a read only file system. Another reason is the kernel code and
> udev rule for device "readiness" means the volume is not "ready" until
> all member devices are present. And while the volume is not "ready"
> systemd will not even attempt to mount. Solving this requires kernel
> and udev work, or possibly a helper, to wait an appropriate amount of

Sth like this? I got such problem a few months ago, my solution was
accepted upstream:
https://github.com/systemd/systemd/commit/0e8856d25ab71764a279c2377ae593c0f2460d8f

Rationale is in referred ticket, udev would not support any more btrfs
logic, so unless btrfs handles this itself on kernel level (daemon?),
that is all that can be done.

> time. I also think it's a bad idea to implement automatic degraded
> mounts unless there's an API for user space to receive either a push
[...]
> There is no amount of documentation that makes up for these
> deficiencies enough to enable automatic degraded mounts by default. I
> would consider it a high order betrayal of user trust to do it.

It doesn't have to be default, might be kernel compile-time knob, module
parameter or anything else to make the *R*aid work.

-- 
Tomasz Pala <gotar@pld-linux.org>