[Meai]

I havent tested that it does work as described but the docs say that the cluster stops working entirely unless the cluster size corresponds to the configured replication. Seen here: https://apple.github.io/foundationdb/configuration.html#conf...

Look under "double" mode or "triple" mode. Is this why it maybe didn't work for you?

[realreality]

I’m not sure if you can switch from single to double, and then back to single. I don’t remember if this configuration was available when I was testing fdb, or if you just increased the number of processes in order to scale the cluster.

I do remember getting into a state where the status said it was migrating data, but there was no available node to migrate it to (because I wanted to shrink the cluster). Effectively, the cluster was deadlocked.

[Meai]

Supposedly it works, as described a section below: https://apple.github.io/foundationdb/configuration.html#chan...

But yeah, the entire point of my comments in this thread is that the database should be telling me exactly what my options are at any situation if there are any. Judging by your comments it seems that you have also encountered a silent "deadlock" and the database gave no indication of what the hell was going on. That's the key here: The database silently stopped working, right? For something as critical as a database with possibly very important data, this just isn't acceptable to me. I want to be told as if I'm a complete noobie user what I have to do and why and what is going on with my data. The database is not a place where I feel the need to put on my smartypants hat, it's where I want to be taken care of completely.