If I could also add that NBD is extremely notorious in Linux. I am a block storage developer and NBD has been one of the main reasons why so many openstack storage products (like formation data and others) have really struggled. There are many known Linux kernel issues with NBD, for example, if an NBD provider (user space daemon) exits for any reason, the kernel panics. Here is an example of a long outstanding bug that has plagued the NBD community and openstack community for years (https://www.mail-archive.com/nbd-general@lists.sourceforge.n...). It won't get addressed any time soon. I also looked at the repo and it looks like a very simplistic approach to a hard problem. BTW I have used etcd and if this is anything like etcd, I'd really be worried. etcd snapshots bring an entire cluster down for a while.