vmstat (virtual memory statistics) is a computer system monitoring tool that collects and displays summary information about operating system memory, processes, interrupts, paging and block I/O. Users of vmstat can specify a sampling interval which permits observing system activity in near-real time. The vmstat tool is available on most Unix and Unix-like operating systems, such as FreeBSD, Linux or Solaris. Syntax The syntax and output of vmstat often differs slightly between different operating systems. # vmstat 2 6 procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 2536 21496 185684 1353000 0 0 0 14 1 2 0 0 100 0 0 0 2536 21496 185684 1353000 0 0 0 28 1030 145 0 0 100 0 0 0 2536 21496 185684 1353000 0 0 0 0 1026 132 0 0 100 0 0 0 2536 21520 185684 1353000 0 0 0 0 1033 186 1 0 99 0 0 0 2536 21520 185684 1353000 0 0 0 0 1024 141 0 0 100 0 0 0 2536 21584 185684 1353000 0 0 0 0 1025 131 0 0 100 0 In the above example the tool reports every two seconds for six iterations. We can get the customized or required outputs by using various options with the vmstat command. # vmstat –s This option is used to get memory statistics. # vmstat –d This option is used to get disk statistics. See also nmon — a system monitor tool for the AIX and Linux operating systems. iostat top sar External links Softpanorama vmstat page Unix software System monitors