Last week I nuked my personal lemmy instance while trying to upgrade to 0.18.0. Due to some technical issues, I decided to keep the server offline while waiting for the new releases. During this process I deleted the database and all config files while trying to debug. Finally, after 1 week, I decided to try the latest release candidate and the instance is back up. I thought I would have to manually re-subscribe to all my communities as I saw an empty list of subscribed communities, but over the next few hours something amazing happened. One by one all my previously subscribed communities appeared on the Communities->All tab 😱 🤯. All I had to do was click subscribe. I guess this would not have happened if I had used a different username or domain name for my instance.
TLDR: Fediverse/lemmy restored my subscribed communities after the instance was offline for 1 week and the database was reset.
Fediverse services are still in development. Unfortunately, the unpleasantness around the site which must not be named forced them to switch their development model to “fuck it, we’ll do it live!”