Hi Balaji,

Disk IO is actually captured and monitored as part of Linux Server Monitoring. Please follow the steps below to view the metrics in the Site24x7 web client:

1. Log in to Site24x7 and go to Server > Server Monitor > Servers > click on the Linux monitor added.
2. Go to the Disks tab and you will be able to view the disk I/O, partition details, a forecast based on your current usage, individual disk utilization and more.
   

Alternatively, you can also go to Reports > Server Monitor > Server Disk Partition Report and select the required monitor from the drop-down Monitors/Tags.

Hope this helps. Please comment in the below thread if you would want to monitor the disk IO individually for each disk. 

Regards

Anita