Solaris Tunable Parameters Reference Manual



Initial trigger for system paging to begin. When this threshold is crossed, the page scanner wakes up to begin looking for memory pages to reclaim.

Data Type

Unsigned long


The greater of 1/64th of physical memory or 512 Kbytes


The minimum value is 512 Kbytes or 1/64th of physical memory, whichever is greater, expressed as pages using the page size returned by getpagesize(3C).

The maximum is the number of physical memory pages. The maximum value should be no more than 30% of physical memory. The system does no enforcement of this range other than that described in the Validation section.




Yes, but dynamic changes are lost if a memory based DR operation occurs.


If lotsfree is greater than the amount of physical memory, the value is reset to the default.


The relationship of cachefree is greater than or equal to lotsfree, which is greater than desfree, which is greater than minfree, must be maintained at all times.

When to Change

When demand for pages is subject to sudden sharp spikes, the memory algorithm might not be able to keep up with demand. One way to work around this problem is to start reclaiming memory at an earlier time. This solution gives the paging system some additional margin.

A rule of thumb is to set this parameter to 2 times what the system needs to allocate in a few seconds. This parameter is workload dependent: a DBMS server can probably work fine with the default settings, but a system doing heavy file system I/O might need to adjust this parameter.

For systems with relatively static workloads and large amounts of memory, adjust this value downwards. The minimum acceptable value is 512 Kbytes expressed as pages using the page size returned by getpagesize(3C).

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