Faulty RAID1 disk now shows as foreign

Solution 1:

DO NOT import the foreign configuration.

A drive shown as "Foreign" is one that the RAID controller thinks is part of a RAID array, but does not recognize as being part of an existing array on that controller. This doesn't commonly happen in your situation. Most of the time you see a foreign configuration when moving drives from one controller to another.

Because your drive is faulty, importing the foreign configuration would only result in a second degraded virtual disk being created with a faulty drive, which is not what you want. Or, worse, the controller deciding it really belongs with the other drive after all, resulting in data corruption.

Just continue with replacing the drive. Once replaced, add the new drive to the existing virtual disk.