Solaris Tunable Parameters Reference Manual - SCN Research

Commitment Level
■
Systems with large numbers of transient files (for example,
mail servers or software build machines) – If large numbers
of files are created and then deleted, fsflush might
unnecessarily write data pages for those files to disk.
Unstable
dopageflush
Description
Data Type
Default
Range
Units
Dynamic?
Validation
When to Change
Commitment Level
Controls whether memory is examined for modified pages
during fsflush invocations. In each invocation of fsflush,
the number of memory pages in the system is determined.
This number might have changed because of a dynamic
reconfiguration operation. Each invocation scans by using this
algorithm: total number of pages x tune_t_fsflushr /
autoup pages
Signed integer
1 (enabled)
0 (disabled) or 1 (enabled)
Toggle (on/off)
Yes
None
If the system page scanner rarely runs, which is indicated by a
value of 0 in the sr column of vmstat output.
Unstable
doiflush
Description
Controls whether file system metadata syncs will be executed
during fsflush invocations. This synchronization is done
every Nth invocation of fsflush where N= (autoup /
tune_t_fsflushr). Because this algorithm is integer
division, if tune_t_fsflushr is greater than autoup, a
synchronization is done on every invocation of fsflush
because the code checks to see if its iteration counter is greater
than or equal to N. Note that N is computed once on
invocation of fsflush. Later changes to tune_t_fsflushr
or autoup have no effect on the frequency of synchronization
operations.
42 Solaris Tunable Parameters Reference Manual • June 2005