Server Analytics
CPU
This is a graph of the CPU Time consumed by the processes on your server.
Idle means there are no processes consuming CPU on the machine. This will go down as cpu is being used i.e there are requests hitting your sites or when background jobs run in your site.
iowait means there are processes waiting for disk operations to finish on your server. This may be reading/writing a big file or loading a table from database into memory.
For database server, servers spike in iowait is generally a sign to upgrade for more memory . This is because it's best practice to give Mariadb as much memory as possible so the database can mostly reside in RAM. This'll make all the database operations fast as memory is faster than disk.
Load Average
If you're not familiar with load average concept in Linux, refer https://www.digitalocean.com/community/tutorials/load-average-in-linux to learn a bit about it.
In the above chart Load Average 1 is the load average in a time frame of 1 minute, Load Average 5 is the load average in a time frame of 5 minutes and so on.
Spike in
Load Average 1may be harmless and normal but a spike inLoad Average 15might be an issue