If I needed to remove a disc from a software mirror for a quick backup before a test, how can I remove it cleanly so that it has a good copy of the OS on it? If I use mdadm to fail then remove it, this would be done while CentOS is running (It’s a mirror of the system disc) and I suspect the data on it would not be in a clean state?

Is there a way to say have it not involved in the mirror after the next boot for instance?

Thanks!
jlc