Varying a Volume Offline

To make a disk volume unavailable to the server for use as a database, recovery log, or storage pool volume, select the appropriate option and then click Finish, or click Cancel.

Wait for Completion

Specify whether to wait for the server to complete processing this command in the foreground.

Yes Specifies that the server processes this command in the foreground. Yes is the default.
No Specifies that the server processes this command in the background.