Monitoring Disk IO in Linux

In the event that you need to monitor disk IO in Linux, you can do so in various ways. With most Linux distributions, these commands are helpful for this :

# Interactively sortable list of processes' current/instantaneous disk I/O, on ten second update interval. Use the arrow keys to switch the sort column :
iotop   --processes   --only   --delay=10

# Similar to the above, but using the total I/O done while monitoring instead of the current value. Update rate here is five seconds :
iotop   --processes   --only   --delay=5    --accumulated

# List all disk devices with their current read/write rates in megabytes :
iostat   -d  -m

# Periodically list each device and its I/O rates in megabytes, ignoring those with no activity :
iostat   -d  -m  -t  -y  -z    10