Serves as the 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.
Unsigned long
The greater of 1/64th of physical memory or 512 KB
The minimum value is 512 KB or 1/64th of physical memory, whichever is greater, expressed as pages using the page size returned by getpagesize. For more information, see getpagesize (3C) .
The maximum value is the number of physical memory pages. The maximum value should be no more than 30 percent of physical memory. The system does not enforce this range, other than that described in the Validation section.
Pages
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 lotsfree being greater than desfree, which is greater than minfree, should be maintained at all times.
When demand for pages is subject to sudden sharp spikes, the memory algorithm might be unable to keep up with demand. One workaround 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. However, you might need to adjust this parameter for a system doing heavy file system I/O.
For systems with relatively static workloads and large amounts of memory, lower this value. The minimum acceptable value is 512 KB, expressed as pages using the page size returned by getpagesize.
Unstable