Resource Usage Tool in cPanel

The Resource Usage tool in cPanel can provide valuable insight on potential causes of sites loading slowly.

Every hosting plan has a limit to its available resources. These resources limit the amount or intensity of the processes it can support. These limits are put in place to prevent the server from being overloaded and crashing.

Higher tiered plans have higher resource limits. 

About Resources

1. All computers and servers are limited in the resources that they have
2. "Resources", refers to the computer's CPU, RAM, Read/Write speeds (I/O), disk space, process limit, among other less notable resources
   1. CPU - Central Processing Unit
      1. The CPU is responsible for all of the logical operations of a computer
      2. Since computers communicate via binary numbers, a series of ones and zeroes, the CPU is always working to perform mathematics on these binary numbers
      3. Through a complex process, these numbers and mathematics are translated to what is seen on the computer screen
      4. With more tasks being performed on the computer, there's a potential that the CPU is not able to keep up with the tasks that are asked of it
      5. A server is simply a high powered computer, and performs nearly all of the tasks that an ordinary computer would with greater intensity, and therefore runs the same risk
   2. RAM - Random Access Memory
      1. The RAM is responsible for storing data that needs to be accessed quickly, at a moments notice
      2. RAM operates extremely quickly compared to a hard drive, or even a solid state drive
      3. When a task is started, data that it may need to use while running is loaded into RAM
      4. By persisting in the RAM, the data can quickly be read or edited as needed
      5. While normal disk space can be used in place of RAM, it is too slow to be used for any purpose other than preventing a complete system failure
   3. I/O - Input/Output
      1. I/O is the speed that data is able to be read and written in the hard drive
      2. Solid state drives have a much higher I/O speed than hard disk drives, but still have a limit to what they're capable of
      3. Copying files, creating archives (zip, tar, gz), creating backups, and caching via plugins all have a larger I/O usage than most other tasks
   4. Network Bandwidth
      1. Network bandwidth is the speed and/or amount of data that can be transferred over the internet
      2. Most of our plans offer unlimited bandwidth, although some do have limits in place
      3. With current technology, bandwidth speed is limited, but the limit is typically much higher than any individual would need
      4. Servers in data centers are commonly limited to 10 gbps, while many individual servers will not exceed 1 gbps
      5. Limits are typically imposed by the internet service provider, due to the limitations of current technology, and therefore trickle down to limits on hosting plans
   5. Process Limit
      1. Processes are the individual tasks that the computer is performing
      2. Although in theory a system could have an unlimited number of processes running, on a server, most processes should only run for a few seconds before completing and shutting down
      3. An excess of processes is an indication that a process is not shutting down as it should
      4. While all computers experience random errors caused by electronic interference that can cause processes to get stuck running, if processes regularly get stuck running there is likely an error in the code of the processes
      5. Process limits are imposed to prevent these stuck processes from using an excess of other resources
3. All of these resources are limited due to limitations in technology, the power used by these components, and the cost of these components

Resource Usage Tool

1. Log Into cPanel
2. Open the Resource Usage tool, located in the Metrics section
3. The Dashboard gives an overview of any limits that were reached in the past 24 hours
   1. It's not uncommon for the lower tiered plans to occasionally reach the resource limits
      
4. The Current Usage tab shows the most pertinent information
   
   1. This page shows the current resource usage, as well as graphs of historical usage
   2. This can be used to easily identify any issues with resource usage in the plan
   3. It's not necessarily alarming to see an occasional, brief spike to the resource limit, as brief spikes are hardly noticed by the user or visitors of sites
   4. It is a concern when a limit is regularly being reached, either several times briefly within an hour, or sustained resource usage at the limit for more than 10-15 minutes
      TIP: Backup plugins taking backups and caching plugins use a lot of I/O. If the I/O usage is reaching the limit, consider disabling backup and caching plugins. Although caching plugins are designed to speed up sites, they can slow sites down when there is not enough I/O available. Backup Manager is a great alternative to backup plugins, as it does not use any of the plan's resources.
5. The Snapshot tab shows usage of individual processes
   1. Since most processes are just PHP, it will not show individual scripts that are causing high resource usage
   2. The processes shown here will show the domain that has executed the process
   3. This can be used to narrow down which sites are using the most resources