The scenario describes an application with fast-growing data, which can quickly consume the available space in a volume. Enabling automatic resizing (volume autosize) on the volume is the most direct and automated method to manage this situation. This feature automatically increases the volume's size by a specified increment when its used space reaches a defined threshold. This prevents the volume from running out of space due to rapid data growth and snapshot consumption, ensuring the application remains online without requiring manual administrator intervention to resize the volume.

B. Enable space reservation on the LUN.

This reserves space within the volume for the LUN, guaranteeing write availability for the LUN itself, but it does not automatically increase the total volume size as data grows.

C. Disable volume snapshot autodelete.

This is counterproductive. Snapshot autodelete is a feature that automatically reclaims space by deleting older snapshots when the volume is nearly full. Disabling it would increase the risk of running out of space.

D. Unmap the LUN.

This is a manual administrative action that makes the LUN inaccessible to the host. It is not an automatic space management feature and would cause an application outage.

1. NetApp ONTAP Documentation

Logical storage management

"Manage volume capacity with autosize": "You can configure a volume to automatically grow in size

up to a maximum size

when it is running out of space. The autosize feature can help you prevent a volume from becoming full and applications from being unable to write data." This directly supports using autosize for managing volumes with growing data.

2. NetApp ONTAP Documentation

SAN administration

"LUN space reservation": "When space reservation is enabled

ONTAP preallocates space for the LUN when it is created. This ensures that data can always be written to the LUN." This confirms that space reservation is for guaranteeing LUN writes

not for automatically growing the parent volume.

3. NetApp ONTAP Documentation

Data protection

"How Snapshot copy autodeletion works": "Snapshot copy autodeletion can help you to automatically reclaim space in a volume or an aggregate when it is running out of space." This shows that disabling this feature would prevent automatic space reclamation

which is contrary to the goal.