fastscan
Parameter
- Description
-
Defines the maximum number of pages per second that the system looks at when memory pressure is highest.
- Data Type
-
Signed integer
- Default
-
The
fastscan
default value is set in one of the following ways:-
The
fastscan
value set in/etc/system.d/file
is used. -
The
maxfastscan
value set in/etc/system.d/file
is used. -
If neither
fastscan
normaxfastscan
is set in/etc/system.d/file
,fastscan
is set to 64 MB when the system is booted. Then, after the system is booted for a few minutes, thefastscan
value is set to the number of pages that the scanner can scan in one second using 10% of a CPU.
In all three cases, if the derived value is more than half the memory in the system, the
fastscan
value is capped at the value of half the memory in the system. -
- Range
-
64 MB to half the system's physical memory
- Units
-
Pages
- Dynamic?
-
Yes, unless dynamic reconfiguration operations that add or delete memory occur. At that point, the value is reset to the value provided by
/etc/system.d/file
or calculated from the new physical memory value. - Validation
-
The maximum value is the lesser of 64 MB and 1/2 of physical memory.
- When to Change
-
When more aggressive scanning of memory is preferred during periods of memory shortfall, especially when the system is subject to periods of intense memory demand or when performing heavy file I/O.
- Commitment Level
-
Unstable