Is Redis data volatile?

Question

I am trying to figure out something and I've been searching for a while with no results.

What happens if a Redis server loses power or gets shut down or something that would wipe the RAM? Does it keep a backup somewhere?

I am wanting to use Redis for a SaaS style app so if I go to app.com/usernamesapp it would use redis to verify usernamesapp exists and get the ID... At which point it would use MySQL for all the rest of the stuff... Reasons being I want to begin showing the page ASAP and most of the stuff is javascript so all the MySQL would happen after the fact.

Thanks

Answer 1

Redis can be configured to write to disk at regular intervals so if the server fails you wont lose your data. http://redis.io/topics/persistence

Answer 2

From the Redis FAQ

Redis is an in-memory but persistent on disk database

So a critical failure should not result in data loss. Read more at http://redis.io/topics/faq