VMSTAT(1) VMSTAT(1) NAME vmstat - report virtual memory statistics SYNOPSIS vmstat [ -fsi ] [ drives ] [ interval [ count ] ] DESCRIPTION _V_m_s_t_a_t delves into the system and normally reports certain statistics kept about process, virtual memory, disk, trap and cpu activity. If given a -f argument, it instead reports on the number of _f_o_r_k_s and _v_f_o_r_k_s since system startup and the number of pages of virtual memory involved in each kind of fork. If given a -s argument, it instead prints the contents of the _s_u_m structure, giving the total number of several kinds of paging related events which have occurred since boot. If given a -i argument, it instead reports on the number of _i_n_t_e_r_r_u_p_t_s taken by each device since system startup. If none of these options are given, _v_m_s_t_a_t will report in the first line a summary of the virtual memory activity since the system has been booted. If _i_n_t_e_r_v_a_l is specified, then successive lines are summaries over the last _i_n_t_e_r_v_a_l seconds. ‘‘vmstat 5’’ will print what the sys‐ tem is doing every five seconds; this is a good choice of printing interval since this is how often some of the statistics are sampled in the system; others vary every second, running the output for a while will make it apparent which are recomputed every second. If a _c_o_u_n_t is given, the statistics are repeated _c_o_u_n_t times. The format fields are: Procs: information about numbers of processes in various states. r in run queue b blocked for resources (i/o, paging, etc.) w runnable or short sleeper (< 20 secs) but swapped Memory: information about the usage of virtual and real memory. Vir‐ tual pages are considered active if they belong to processes which are running or have run in the last 20 seconds. A ‘‘page’’ here is 1024 bytes. avm active virtual pages fre size of the free list Page: information about page faults and paging activity. These are averaged each five seconds, and given in units per second. re page reclaims (simulating reference bits) at pages attached (found in free list) pi pages paged in po pages paged out fr pages freed per second de anticipated short term memory shortfall sr pages scanned by clock algorithm, per-second up/hp/rk/ra: Disk operations per second (this field is system depen‐ dent). Typically paging will be split across several of the available drives. The number under each of these is the unit number. Faults: trap/interrupt rate averages per second over last 5 seconds. in (non clock) device interrupts per second sy system calls per second cs cpu context switch rate (switches/sec) Cpu: breakdown of percentage usage of CPU time us user time for normal and low priority processes sy system time id cpu idle If more than 4 disk drives are configured in the system, _v_m_s_t_a_t dis‐ plays only the first 4 drives, with priority given to Massbus disk drives (i.e. if both Unibus and Massbus drives are present and the total number of drives exceeds 4, then some number of Unibus drives will not be displayed in favor of the Massbus drives). To force _v_m_s_t_a_t to display specific drives, their names may be supplied on the command line. FILES /dev/kmem, /vmunix SEE ALSO _s_y_s_t_a_t(1), _i_o_s_t_a_t(1) The sections starting with ‘‘Interpreting system activity’’ in _I_n_s_t_a_l_l_i_n_g _a_n_d _O_p_e_r_a_t_i_n_g _4_._2_b_s_d. 4th Berkeley Distribution March 15, 1986 VMSTAT(1)