iostat

iostat is one of the many useful sysstat tools available on Linux that print out reports and statistics about the system. This tool in particular gives detailed stats about storage devices and partitions. It also provides some brief stats about the CPU.

• Installing the tool is easy:

$ sudo apt install sysstat

• When run without any arguments, it summarizes the cumulative utilization of CPU and storage devices since the system was last booted:

$ iostat
Linux 5.4.0-1028-raspi (joe-rpi)      02/15/21        _aarch64_       (4 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           2.29    0.01    3.65    9.72    0.00   84.32

Device             tps    kB_read/s    kB_wrtn/s    kB_dscd/s    kB_read    kB_wrtn    kB_dscd
dm-0              0.07         0.01        25.60         0.00       3317   14197808          0
loop0             0.00         0.00         0.00         0.00        970          0          0
loop1             0.00         0.00         0.00         0.00        954          0          0
mmcblk0           0.45         7.44         4.72       436.97    4128807    2619145  242335269
sda              28.69         0.02       855.15         0.00      11137  474249512          0

• To get just the CPU utilization:

$ iostat -c

• To get just the storage device utilization:

$ iostat -d

• If your storage devices have more than one partition, it is useful to get a breakdown of the storage device utilization across device partitions:

$ iostat -p
$ iostat -dp

• To get a running report with a 2-second interval (delay):

$ iostat 2

You need to use Ctrl+C to exit.

• To get a running report with a 2-second interval and stop after 5 reports:

$ iostat 2 5

• To get a running report with a 2-second interval, but skip the stats-since-boot first report:

$ iostat -y 2

Note that iostat -y will not give you the current stats report. It will just behave like iostat and print the cumulative stats-since-boot.

Tried with: sysstat 12.2.0 and Ubuntu 20.04