How do thin provisioning and thick provisioning differ in ONTAP?

• A. Thin provisioning allocates space on demand; thick provisioning reserves entire space upfront.
• B. Thin provisioning reserves space upfront; thick provisioning allocates on demand.
• C. They are the same.
• D. Thick provisioning uses dynamic allocation.

Answer: (A)

Thin provisioning allocates space on demand as data is written, so the logical volume can be larger than the physical space actually allocated at any given moment. This lets you overcommit to some extent and use storage more efficiently, since blocks are only taken from the pool when you store data.

Thick provisioning reserves the entire space upfront when the volume is created, guaranteeing that much physical capacity is dedicated to that volume from the start. This provides predictable capacity and performance, but it wastes space if the volume isn’t fully used later.

So the statement that thin provisioning allocates space on demand and thick provisioning reserves all space upfront is the correct description.