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.

For more information on CIFS oplocks, see the CIFS section of the File Access and Protocols Management Guide.

When to turn CIFS oplocks off

CIFS oplocks on the storage system 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 storage system.

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 storage system are turned off.
If you set the cifs.oplocks.enable option back to On, CIFS oplocks are enabled for the storage system, and the individual setting for each qtree and volume takes effect.

Enabling CIFS oplocks for a specific volume or qtree

To enable CIFS opslocks for a specific volume or a qtree, complete the following steps.

Step	Action
1	Make sure the global `cifs.oplocks.enable` option is set to On.
2	Enter the following command: *qtree oplocks path* enable** path is the path name of the volume or the qtree.
3	To verify that CIFS oplocks were updated as expected, enter the following command: qtree status vol_name vol_name is the name of the specified volume, or the volume that contains the specified qtree.

Step

Action

Make sure the global cifs.oplocks.enable option is set to On.

Enter the following command:

qtree oplocks path enable

path is the path name of the volume or the qtree.

To verify that CIFS oplocks were updated as expected, enter the following command:

qtree status vol_name

vol_name is the name of the specified volume, or the volume that contains the specified qtree.

Example

To enable CIFS oplocks on the proj1 qtree in vol2, use the following commands:

system1> options cifs.oplocks.enable on

system1> qtree oplocks /vol/vol2/proj enable

Disabling CIFS oplocks for a specific volume or qtree

To disable CIFS opslocks for a specific volume or a qtree, complete the following steps.

Attention
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	Enter the following command: *qtree oplocks path* disable** path is the path name of the volume or the qtree.
2	To verify that CIFS oplocks were updated as expected, enter the following command: qtree status vol_name vol_name is the name of the specified volume, or the volume that contains the specified qtree.