Configuring RESUMate for a Windows XP/2000/2003/NT Server

The following article from Microsoft's support site deals with configuring a Windows 2000 Server to disable Opportunistic Locking. Many RESUMate customers have found that applying this change helps maintain a stable RESUMate database file. This same information applies when configuring a Windows XP, Server 2003,  or Windows NT server.

To simplify the process of disabling Opportunistic Locking, you can download and run the following utility:
set_oplocks.exe

Please note that this only needs to be done on a Windows XP/2000/2003/NT machine acting as the file server. This includes peer-to-peer network environments as well as dedicated server environments.

Configuring Opportunistic Locking in Windows 2000 (Q296264)

The information in this article applies to:

Summary

Windows 2000 server message block (SMB) clients can disable opportunistic locking, so that those clients can lock files and locally cache information without the risk of another user changing the file. This increases performance for many file operations, but may decrease performance in other operations, because the server that grants the opportunistic lock must manage the breaking of that lock when another user requests access to the file.

More Information

The location of the client registry entry for opportunistic locking has changed in Windows 2000 from the earlier location in Microsoft Windows NT. In Windows 2000, the registry entry that disables opportunistic locking is:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MRXSmb\Parameters
\OplocksDisabled\REG_DWORD 0 or 1
Default: 0 (not disabled)

You can also set Windows 2000 to deny the granting of opportunistic locks by setting the following registry entry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters
\EnableOplocks\REG_DWORD 0 or 1
Default: 1 (true)

In addition, you can use the following values to tune opportunistic locking for Windows 2000-based computers that have granted opportunistic locks.

The following value specifies the minimum link throughput that the server allowed before it disables raw and opportunistic locks for this connection:

MinLinkThroughput\REG_DWORD 0 to infinite bytes per second
Default: 0

The following value specifies the maximum time that is allowed for a link delay. If delays exceed this number, the server disables raw I/O and opportunistic locking for this connection:

MaxLinkDelay REG_DWORD 0 to 100,000 seconds
Default: 60

The following value specifies the time that the server waits for a client to respond to an oplock break request (smaller values allow detection of crashed clients more quickly, but might potentially cause loss of cached data):

OplockBreakWait \ REG_DWORD 10 to 180 seconds
Default: 35