Section 6.2. vmstat(1M) Command

6.2. vmstat(1M) Command

The vmstat command summarizes the most significant memory statistics. Included are summaries of the system's free memory, free swap, and paging rates for several classes of usage. Additionally, the -p option shows the paging activity, page-ins, page-outs, and page-frees separated into three classes: file system paging, anonymous memory paging, and executable/shared library paging. You typically use the -p option for a first-pass analysis of memory behavior.

The example below illustrates the vmstat command. Table 6.2 describes the columns. We discuss the definitions and significance of the paging statistics from vmstat in Section 6.18.

sol8$ vmstat -p 3      memory          page          executable      anonymous      filesystem    swap  free  re mf  fr  de  sr  epi  epo  epf  api  apo  apf  fpi  fpo  fpf  2410424 516556 7 41   0   0   1    0    0    0    0    0    0  127  446    0  2356376 472424 8  5   0   0   0    0    0    0    0    0    0   12  228    0  2356376 472032 7  0   0   0   0    0    0    0    0    0    0    0   98    0  2356376 471800 0  0   0   0   0    0    0    0    0    0    0    0    0    0  2356376 471712 0  0   0   0   0    0    0    0    0    0    0    0    0    0 

Table 6.2. Statistics from the vmstat Command

Counter	Description
swap	Available swap space in Kbytes.
free	The amount of free memory as reported by vmstat, which reports the combined size of the cache list and free list. Free memory in Solaris may contain some of the file system cache.
re	Page reclaimsThe number of pages reclaimed from the cache list. Some of the file system cache is in the cache list, and when a file page is reused and removed from the cache list, a reclaim occurs. File pages in the cache list can be either regular files or executable/library pages.
mf	Minor faultsThe number of pages attached to an address space. If the page is already in memory, then a minor fault simply reestablishes the mapping to it; minor faults do not incur physical I/O.
fr	Page-freesKilobytes that have been freed either by the page scanner or by the file system (free-behind).
de	The calculated anticipated short-term memory shortfall. Used by the page scanner to free ahead enough pages to satisfy requests.
sr	The number of pages scanned by the page scanner per second.
epi	Executable and library page-insKilobytes of executable or shared library files paged in. An executable/library page-in occurs whenever a page for the executable binary or shared library is brought back in from the file system.
epo	Kilobytes of executable and library page-outs. Should be zero, since executable pages are typically not modified, there is no reason to write them out.
epf	Kilobytes of executable and library page-freesKilobytes of executable and library pages that have been freed by the page scanner.
api	Anonymous memory page-insKilobytes of anonymous (application heap and stack) pages paged in from the swap device.
apo	Anonymous memory page-outsKilobytes of anonymous (application heap and stack) pages paged out to the swap device.
apf	Anonymous memory page-freesKilobytes of anonymous (application heap and stack) pages that have been freed after they have been paged out.
fpi	Regular file page-insKilobytes of regular files paged in. A file page-in occurs whenever a page for a regular file is read in from the file system (part of the normal file system read process).
fpo	Regular file page-outsKilobytes of regular file pages that were paged out and freed, usually as a result of being paged out by the page scanner or by write free-behind (when free memory is less than lotsfree + pages_before_pager).
fpf	Regular file page-freesKilobytes of regular file pages that were freed, usually as a result of being paged out by the page scanner or by write free-behind (when free memory is less than lotsfree + pages_before_pager).