You get many LDF/Resource Usage emails from your server?
LFD service sends excessive resource usage alerts normally to root user.
This notification points out a particular process or service using excessive server resources. Information included on this email helps identifying the resource eating process/service.

We can either kill/stop the process/service to free the resource or allocate more resource to it, if necessary.
Disabling these alerts is not always a good idea and in some cases it might be a security issue...on which we won't be alerted, so be very careful when and why if you proceed with this.
A good solution is to identify the issue and if you have a process you know for sure it's not dangerous (for instance netdata monitor runs all the time...so LFD will send out tons of notifications which we might not need) then add it to /etc/csf/csf.pignore (using SSH and your favorite editor edit the file mentioned) .
The pignore of CSF will ignore the particular process/service included in it and hence disables the LFD alerts
Another method, is to increase the 2 values PT_USERMEM and PT_USERTIME to higher numbers in order to minimize or disable the alerts.
Setting those to high values actually makes them non-usable.
PT_USERMEM = 500
PT_USERTIME = 150000
Setting those values to 0 will totally disable the alerts and this is NOT suggested.
Once you edit the above values, save and restart CSF to activate those settings.