On Mon, Apr 29, 2019 at 2:38 PM Austin S. Hemmelgarn <[email protected]> wrote:
> * If you're doing this on a system using systemd, it actually doesn't do > what you are trying to do. Systemd will refuse to mount the volume if > all the constituent devices aren't present, > It is not quite correct. systemd will not even attempt to mount incomplete btrfs because it will wait for all devices (including missing ones) to appear before proceeding to mount it. And if this check is disabled, it will actually just call mount.btrfs, it will certainly not "refuse" to do anything. So the following may work - disable udev rule calls "btrfs device ready" (it actually calls internal variant, but it does not matter). - replace mount.btrfs with your own script that tries to mount btrfs and if it fails tries to mount it degraded.
