Hello,
I am running Moodle version 3.10 (Build: 20201109) as a cluster within AWS, on Centos 7 with PHP 7.4 and OpenResty 1.19.3.
Everything is running very smoothly and stable, however I am having some issues with configuring AWS Elasticache Redis to handle Application and Session cache. Although stable, I do have some slow page loads which I believe enabling the Redis cache store for application cache will help to improve. I have done other performance tweaks such as: only enabling Moodle modules I need, configured xsendfile (X-Accel-Redirect), amongst a few other things which have all had notable performance and stability improvements.
I have also followed the instructions on this page (https://docs.moodle.org/310/en/Redis_cache_store) for setting up the Redis cache store including the step for setting up the mappings - "Stores used when no mapping is present".