For UNIXes that support kernel based (currently only Linux), this parameter allows the use of them to be turned on or off. However, this disables Level II oplocks for clients as the Linux kernel does not support them properly. Kernel oplocks support allows Samba oplocks to be broken whenever a local UNIX process or NFS operation accesses a file that smbd 8 has oplocked. This allows complete data consistency between SMB/CIFS, NFS and local file access (and is a very cool feature :-). If you do not need this interaction, you should disable the parameter on Linux to get Level II oplocks and the associated performance benefit. This parameter defaults to no and is translated to a no-op on systems that do not have the necessary kernel support. oplocks level2 oplocks smb2 leases no