After running with OptimumCache for a year, we realize that it does not significantly improve the performance of servers, but in some cases creates support and performance issues. Therefore, we’ve decided to retire OptimumCache feature as of now.
There is nothing you need to do about it if you never enabled it. If you did, it will just become non-operational, and will not cause any issues, however, if you’d like to remove OptimumCache from your CloudLinux OS installation, follow steps outlined in this documentation article.
In the future, if we find a way to achieve better results from OptimumCache, we will re-integrate the feature into the CloudLinux OS.