sar -p # paging
sar -d # disk i/o
top # press "o", then press "N" repeatedly until "mem" is at the top, then press enter
# In newer versions of top, the "Cpu(s)" line at the top has an entry labeled "wa".
# This is iowait, and indicates the amount of CPU time spent waiting for any I/O operation to finish.
iostat
iotop