How to troubleshoot redis high CPU usage? And how to limit Redis CPU usage?

Solution 1:

I was also having problems with redis CPU usage. My case was many redis connections (clients) and linux default ulimit of 1024 open files.

High CPU usage could be caused by some CPU intensive operations like smembers.

You can also use the SLOWLOG redis command to log the long running commands.

The best you can do to trace the problem, when no log and SLOWLOG results, is to strace the redis process and see what is going on. For my case it was 'Too many open files' error, but it was only seen in strace output, which was solved by increasing default nr of files limit over 1024.