NetApp
Storage > Volumes : Managing volumes : Changing your volume state

Changing your volume state
You can change the state of your volume when you want to take your volume offline, bring it back online, or restrict access to your volume. However, you cannot take a root volume offline.
Steps 
1.
From the Home tab, double-click the appropriate storage system.
2.
In the navigation pane, click Storage > Volumes.
3.
Select the volume for which you want to modify the state.
4.
From the Status menu, click the volume state you want.
5.
In the confirmation dialog box, click Offline or Restrict, as appropriate.
No confirmation is required to bring a volume online.