For UNIXes that support kernel based (currently only IRIX and the Linux 2.4 kernel), this parameter allows the use of them to be turned on or off. However, this disables Level II oplocks for clients as the Linux and IRIX kernels do 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 and IRIX to get Level II oplocks and the associated performance benefit. This parameter defaults to on, but is translated to a no-op on systems that no not have the necessary kernel support. You should never need to touch this parameter. oplocks level2 oplocks yes