Changing the CIFS oplocks setting

What CIFS oplocks do

CIFS oplocks (opportunistic locks) enable the redirector on a CIFS client in certain file-sharing scenarios to perform client-side caching of read-ahead, write-behind, and lock information. A client can then work with a file (read or write it) without regularly reminding the server that it needs access to the file in question. This improves performance by reducing network traffic.

When to turn CIFS oplocks off

CIFS oplocks on the filer are on by default.

You might turn CIFS oplocks off on a volume or a qtree under either of the following circumstances:

You are using a database application whose documentation recommends that CIFS oplocks be turned off.
You are handling critical data and cannot afford even the slightest data loss.

Otherwise, you can leave CIFS oplocks on.

Effect of the cifs.oplocks.enable option

The cifs.oplocks.enable option enables and disables CIFS oplocks for the entire filer. The setting of the cifs.oplocks.enable option must be consistent with the volume or qtree oplocks settings.

Setting the cifs.oplocks.enable option has the following effects:

If you set the cifs.oplocks.enable option to Off, all CIFS oplocks on all volumes and qtrees on the filer are turned off.
If you set the cifs.oplocks.enable option back to On, the setting for each qtree and volume takes effect and CIFS oplocks are turned on for those volumes and qtrees in which CIFS oplocks are enabled.

Changing the CIFS oplocks setting

To change the CIFS oplocks setting of a volume or a qtree, complete the following steps.

Caution
If you disable the CIFS oplocks feature on a volume or a qtree, any existing CIFS oplocks in the qtree will be broken.

Step	Action
1	If you want...	Then...
	CIFS oplocks to be enabled for the entire filer	Enter the following command: options cifs.oplocks.enable on
	CIFS oplocks to be disabled for the entire filer	Enter the following command: options cifs.oplocks.enable off
2	Enter the following command to enable or disable CIFS oplocks on a specified volume or qtree: *qtree oplocks path* [enable \| disable]** path is the path name of the volume or the qtree. `enable` enables CIFS oplocks. `disable` disables CIFS oplocks.