I’m trying to use a shiny new AWS serverless service valkey which is a drop in replacement for redis. Being serverless it runs as a cluster. I’m currently using redis for session and server wide caching, when switching to a clustered redis service (valkey) server wide caching allows me to tell it that “redis” is a cluster and works fine. Session caching on the other hand informs me that

Session storage does not support redis cluster. Redis server being used in caching is enabled in cluster mode.

I am using cf2021 currently and I’m fairly sure this has been the same since at least cf2016 - maybe it will work in cf2023 / cf2025? Anyone got any idea why sessions can’t use redis clusters as it seems like a very odd situation to allow it for some things but not others?

I don't have an answer, but I can confirm that we recently discovered that CF2021 doesn't work with a Redis cluster, at least with Standard. We switched to using a non-clustered AWS ElastiCache Redis serverless instance and now it's happy.

There may be a technical reason for it not working, but I would guess it hasn’t been looked at for a long time by Adobe - I’m using enterprise so the license doesn’t help

We are using a clustered AWS Redis server with CF2016 Enterprise, no issues.

@Robb is that for sessions? I can get it to work for the global cache ok

Yes, we use it for session storage.

hmm, how did you manage to configure that?

I didn't, it was configured when I started here but I'd be happy to compare settings if you want?

I’d be interested in what the “Memory Variables” screen says for the redis options, I had to tick an option that said “Reuse redis caching server” but thats where it fails. Connecting directly to the redis cluster fails on that page