I'm including in this post the various fixes and optimizations that have made Redis stable on an RHEL 6.5 system with 2GB of memory. I currently run NodeBB/Redis behind a Varnish Cache + nginx combo. Switching to nginx was easy and significantly cut my memory usage.
Close dead and idle peers to free up connections. This was my biggest problem that would eventually cause NodeBB to fail to connect and elicit the _csrf error. On RHEL/CentOS, Redis does not by default seem to be configured to close idle connections. Thus, whenever your forum will crash is predictable at a linear rate, where the beta is your avg. number of visitors.timeout 120 tcp-keepalive 60 /etc/security/limits.conf
Increase the maximum number of open files for Redis and your web server.
redis soft nofile 65536
redis hard nofile 65536
nginx soft nofile 262144
nginx hard no file 262144
}Last, make sure you enable nginx to start on boot: `sudo chkconfig nginx on`