Adrien There will always be the wonderful and favorite client that tweaks things they know nothing about and breaks things.
Personally I don't mind.... Just like if they go into wordpress and mess up the theme, it can be billable time to fix it so it doesn't really cost you anything. Then again I don't work with customers who would have issue paying me for an hour of time to undo their mistake. If its just click restore I wouldn't charge the first time or if its just occasional.
Depending on if you use a ticketing system or any screen before they can submit a ticket, you could make a knowledge base article that pops up based on redis problem keywords. Just have the correct settings they can copy and paste in that article.