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What does it mean if we see swpq-sz > 150 and %swpocc at 100%? (Doc ID 1951933.1)

Last updated on JULY 07, 2023

Applies to:

Solaris Operating System - Version 8.0 and later
Information in this document applies to any platform.


Why do we see permanently swpocc at 100% in sar?

# sar -q

SunOS <hostname> 5.10 Generic_150401-05 i86pc    11/24/2014

00:00:00 runq-sz %runocc swpq-sz %swpocc
14:30:00     1.5      18   201.9     100
14:40:00     1.5      22   201.0     100
14:50:00     1.3      16   201.0     100

Average      1.5      17   200.1     100

Solaris will swap out threads in case of a memory shortage and these threads will be listed on the swap queue.

sar -q will show the length of the swap queue (swpg-sz) and a percent value for swpocc :

    -q             Reports average queue length while  occupied,
                    and percent of time occupied:

                    runq-sz, %runocc    Run   queue   of   kernel
                                        threads   in  memory  and

                    swpq-sz, %swpocc    Swap queue of processes

swpocc is part of the sysinfo structure. The value will be checked and updated every second among others like runque, runocc etc.

If the value for %swpocc is constantly at 100% it is nothing to worry about. As it only means, that we have at least 1 thread in the swap queue during the measured interval.


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