Paging

When a process causes a page fault because of missing data, this data is "paged in". When a process is forfeiting memory the data is "paged out" to swap, subsequently when this data is needed again it is "paged in" again. Paging is different from swapping because swapping moves the entire memory of a process to/from swap. Paging is performed in units of that are of pagesize bytes. Different architectures have different sizes of pages.

To find the pagesize of your system try typing "pagesize".

$ pagesize 4096

Here is sample output from a Solaris 8 production system that is experiencing mild paging, but zero swapping:

[root@soemhost /tmp]# vmstat -S 60 procs    memory            page            disk          faults      cpu r b w  swap  free  si  so pi po fr de sr m1 m1 m1 m2   in   sy   cs us sy id   0 0 0 1591144 1483816 0  0 574 2  2  0  0  0  0  0  1  843 1729  457  6 13 82 0 0 0 1164512 1051184 0 0 42  6  6  0  0  0  0  0  0  729 2268  222  3 30 66   0 0 0 1253864 1060440 0  0 17  3  3  0  0  2  2  2  1  500 1977  217  6 33 60   0 0 0 1208336 1058672 0  0 50  8  8  0  0  1  1  1  0  681 2947  252  5 35 60