I'm not blaming unraid for the clone disk having the same UUID, but it's not that bizarre a situation. The issue is that having a clone UUID on an unrelated spare disk broke unraid's process for adding a cache drive, in a way that could have caused some real problems. I would just suggest that they sanity-check the output of the btrfs command before using it as the input for another btrfs operation.
[6.7.0] Adding drive to cache pool fails when clone of data drive present
in Stable Releases
Posted
I'm not blaming unraid for the clone disk having the same UUID, but it's not that bizarre a situation. The issue is that having a clone UUID on an unrelated spare disk broke unraid's process for adding a cache drive, in a way that could have caused some real problems. I would just suggest that they sanity-check the output of the btrfs command before using it as the input for another btrfs operation.