Technology Notebook

Windows::File Locking Issues

Client Settings for Windows 2000, XP, 2003 Acting as a Workstation or Client

To modify the settings for the Workstation service, it is necessary to edit the registry, since Microsoft does not provide any method of configuring these options in their client setup. The registry key path is:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\LanmanWorkstation\Parameters

It will be necessary to add the following values as they are listed below, with the proper data type and the value listed (0 in all cases):

Setting Data Type Should be
UseLockReadUnlock
REG_DWORD
0

Indicates whether the redirector uses the lock-and-read and
write-and-unlock performance enhancements.

When this value is enabled, it generally provides a significant
performance benefit. However, database applications that lock
a range and don’t allow data within that range to be read will
suffer performance degradation unless this parameter is disabled.

UtilizeNtCaching
REG_DWORD
0

Indicates whether the redirector uses the cache manager to cache
the contents of files. Disable this parameter only to guarantee that
all data is flushed to the server immediately after it is written by the application.


Opportunistic locking is controlled differently in the newer versions of Windows than was done in Windows NT. The following registry key path is the location of the desired entry and that must be present and set to the associated value.

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\MRXSmb\Parameters

Setting Data Type Should be
OplocksDisabled
REG_DWORD
1

The OplocksDisabled registry value configures Windows clients to either request or not request opportunistic locks on a remote file.