5.5 Modifying the WSM system cache settings
On Windows Operating System, if WSM Streaming server was up for a few days with active or idle
streaming sessions, system’s available memory will steadily decrease. Server will eventually run out of
memory. This was caused by the Windows’ file system cache. Since Windows gives priority to the
System Cache over application processes, and there is no upper limit on file system cache size on certain
Windows systems, running the streaming service for extensive period will end up with a huge file system
cache due to the large numbers of file I/O requests made by WSM Streaming service. This problem is
not unique to WSM. It applies on any windows services or applications which use heavy file I/O calls.
Problem is also more apparent on 64-bit Windows Operating Systems.
Starting on release 4.0.1, Wyse incorporated a subset of MS’s Dynamic Cache Service into WSM server
to limit the maximum system cache size on 64-bit OS. At this time, there is no workaround for 32-bit
versions of Windows.
When WSM Authentication service starts, it launches SetCache64.exe provided that the registry entry
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Wyse\WSM\LS\SkipSetCache does not exist
or is set to 0 (DWORD). If the registry entry exists and is set to any non-zero value, Setcache64 will not
run and the cache settings will not be modified.
SetCache64.exe sets the maximum system cache size according to below registry setting:
represents desired System Cache Size upper limit.
The accepted values are:
0 (default) – Setting the value to 0 will let the system to automatically assign the memory limit based
on the amount of available memory. The more memory available, the higher percentage of that
memory will be allocated to the System Cache.
Maximum System File Cache Size
Available Memory * 50%
> 2GB & < 8GB
Available Memory * 75%
Available Memory * 85%
However, if the Authentication Server is restarted, the amount of available memory at that time may
be less than when the server was first started, and therefore, the amount of System Cache memory
will also be less.
1-99 - Limit the maximum size of the System File Cache to the specified percentage of currently
available memory. The same restriction for setting the value to zero is true here as well. If the
Authentication server is restarted and the amount of available memory is less, then the size of the
System Cache will also become less.
100-199 – These values have no meaning and will be rounded up to 200.
> 200 - Limit the maximum size of the System File Cache to x Mbytes