Hi! Glad to hear that you are enjoying using Sentry! 
Unfortunately, there is no way to recreate this data. That said if you use our on-premise repository for your install, it automatically sets up retention for Redis. – Scratch that, I only started doing that in the v10 branch, sorry 
This will also stop being an issue with Sentry v10 as it will use ClickHouse for these charts, which is persistent by default.
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