OK I have flushed the cache of rendered JPEGs and ordered another 50GB of disk quota (was 9GB). That should take care of things.
Until the new quota comes on stream I'll reduce the caching of rendered JPEGs drastically as that what was causing the issue -- purging them freed about 3GB. I guess a lot of people are experimenting with the new bindings for Ch4.
Perhaps a moderator would be kind enough to do the usual: close this one and edit the OP to point to the successor. Please don't delete this thread as I still need to go through it and create tickets for the unrecognized devices.