In order to calculate the volumes I/O metrics, a Machine Agent must use the disk file system command or df as well as the cat /proc/diskstats command in Linux. Then the Machine Agent matches the mount point and file system names of both of the command outputs.
If the output of df is:
Filesystem 1K-blocks Used Available Use% Mounted on
udev 368708 4 368704 1% /dev
tmpfs 75884 948 74936 2% /run
/dev/sda1 11479264 6694412 4178696 62% /