Latest experiences disconnecting the external closures whem computer is running.
Drivepool seems to go easy with this - I am able to put my pooldrive offline in Windows-Diskmanager.
When back online Drivepool recognizes this and puts pool online again.
However I am seeing some BSODs from the marvell-driver mvs91xx.sys driving the external closures.
So, Drivepool would be able to handle this, my OS (Win8) is complaining.
Not great of an issue as the enclosures are only the backups and not used all the time, so I will do a proper shutdown to switch off the enclosures.
Switching on while OS running is not an issue.
Migrating on the HTPC from simple use of junctions to Drivepool worked as well.