No data for disk metrics

Why do I see 'No Data Available' for the metrics Disk Busy and Idle Percentage and Disk IOPS in Linux monitoring?

The Linux monitoring agent uses the utility iostat to capture disk idle and busy percentage and disk IOPS metrics. Please ensure the iostat utility is installed in your server. If not, please install it in the server and restart the monitoring agent service.

Please follow the steps below:
  1. Install the iostat utility
    1. For Debian:
      apt-get install sysstat
    2. For CentOS, Fedora, RHEL:
      yum install sysstat
  2. Execute the below command to check if the iostat utility is installed successfully:
    iostat -x-d
  3. Restart the agent service:
    sudo /opt/site24x7/monagent/bin/monagent restart