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Do you use Redis as the master data store? Are you using Redis Cluster, or unclustered? My concern with Redis is reliability. Redis Cluster has problems with c
by lobster_johnson 11y ago
Do you use Redis as the master data store? Are you using Redis Cluster, or unclustered?
My concern with Redis is reliability. Redis Cluster has problems with consistency [1], whereas unclustered Redis -- well, it syncs to disk every 10 seconds or so, but even then I'm concerned that the reliability of its on-disk structures haven't been as battle-tested as, say, PostgreSQL. Or has it?
[1] https://aphyr.com/posts/307-call-me-maybe-redis-redux https://aphyr.com/posts/307-call-me-maybe-redis-redux
- fweespeech 11y ago> well, it syncs to disk every 10 seconds or so Yeah, about that: http://redis.io/topics/persistence http://redis.io/topics/persistence > Using AOF Redis is much more durable: you can have different fsync policies: no fsync at all, fsync every second, fsync at every query. With the default policy of fsync every second write performances are still great (fsync is performed using a background thread and the main thread will try hard to perform writes when no fsync is in progress.) but you can only lose one second worth of writes.
- lobster_johnson 11y agoRDB is what I was thinking of. I didn't know they had added a write-ahead log. It seems you can combine RDB and AOF, which is nice.
- fweespeech 11y agoYeah, you can. Its quite nice, the only real problem with it is the reliability of the clustering is subpar. If you are happy with a Master/Slave setup and occasionally having to deal with data loss due to Master failures [e.g. losing a second or two of data that wasn't replicated], it works nicely. Just realize I wouldn't use Redis as a long term persisting of data because of issues like this: https://muut.com/blog/news/april-2014-service-failure.html https://muut.com/blog/news/april-2014-service-failure.html