I use OpenSUSE Leap with transactional server, which is another immutable distribution by SUSE. I run it on my storage node primarily serving a ZFS pool over the network. This means the server is more like an appliance (NAS) and this immutable setup is a perfect fit IMO.

I suppose I could have use Aeon instead? But I like having OpenSUSE Leap across the fleet too which others doing more heavy lifting.