I got this error for every request this morning.
MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error.
It looks like the issue happens when we're saving to the cache. I checked the rdb files on ores-redis-01 and found that the cache rdb file was exactly 1000MB, but the config put the max memory at 3GB. I restarted redis and the service recovered. The 1000MB rdb file grew to 1001MB in a minute and then the same error started happening.
So I ran config set stop-writes-on-bgsave-error no in the redis-cli for 6380. That seems to have recovered ORES, but it means we're probably not persisting to disk anymore.