iostat - Report Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions.
To see the statistics of your disk and partitions run the following iostat command:
# iostat -mx -h -p /dev/sdb 3
-m Display statistics in megabytes per second
-x Display extended statistics
-h Make the Device Utilization Report easier to read by a human
-p Displays statistics for block devices and all their partitions
that are used by the system
/dev/sdb - disk to be tested
3 The interval parameter specifies the amount of time in seconds between each report.
Example for two disks, sda and sdb including partitions:
# iostat -mx -h -d -p /dev/sda -p /dev/sdb 3
# whereis iostat
iostat: /bin/iostat /usr/bin/iostat /usr/share/man/man1/iostat.1.gz
# man 1 iostat