My entire 1.5 year history is a 350mb file, around 17000 notes, not that much data really. If you're concerned about losing notes run a backup relay. There's options for umbrel, start 9, Citrine on Android, I think even one for old windows. 

 Absolutely. But for relays relaying a ton of users I have to expect that my notes may not persist indefinitely.

Yes, for users that worry about theit notes being deleted, running their own relay is a solution.

I responded to claims that notes are persistent. They might be, we don't know that yet. 

 They *should* be deleted from the relays almost immediately. If users want to keep his own notes, or someone else's, they should simply download them and store them themselves.