View disk activity in Activity Monitor on Mac
View the disk activity on your Mac in the Activity Monitor window or in the Dock.
In the Activity Monitor app on your Mac, do any of the following:
To see disk activity, click Disk in the Activity Monitor window (or use the Touch Bar).
Activity Monitor tracks the number of times your Mac accesses the disk to read and write data, and shows the amount of data that’s read or written to your disk.
To see a graph of disk activity in the Dock, choose View > Dock Icon > Show Disk Activity.
To display more columns, choose View > Columns, then choose the columns you want to show.