Comment 81 for bug 120375

I think it can be understood that using "mdadm --assemble --scan" instead of doing selective "mdadm --run <device>" calls on all devices ${ROOT} depends on could be a reasonable and quick fix, if the information is not available somwhere allready. Full support here.

My interest lies in getting the algorithm right, so that it will work out for most if not all possible ways of udev,raid,crypt,lvm, etc. stacked configs. And we won't hit a whole waterfall of subsequent bugs.

Also configuring selective arrays to be run or not run degraded might be somthing that can be postponed. The list of md devices that are needed to fully bring up a server or desktop system consists of the md devices on which the devices listed in fstab depend on.

When a disk fails in a running system, it doesn't stop by default, and probably should't. This is the reason for the mdadm notification functionality. So defaulting to bootdegraded=yes seems reasonable, once the patches are tested to work with enough configurations, and will be safe if no other md devices than the ones neccessary to set up the fstab are touched.

https://wiki.ubuntu.com/BootDegradedRaid updated