Is it possible to create a Space Reserved LUN in a volume without a Space Guarantee?

OLAFNETAPP — Thu, 05 Jun 2025 06:42:36 GMT

We have a volume that has a Space Gurantee of NONE. There's 3.5 TB left. We'd like to create a Space Reserved LUN of 3TB in this volume but whenever I try the LUN is always thin-provisioned.

Is it at all possible to create this LUN with Space Reservation? If not, can we safely change the volume to have a Space Guarantee of Volume (it IS a flexible volume)

Running Ontap 7.3.2P6

Is it possible to create a Space Reserved LUN in a volume without a Space Guarantee?

SEANMLUCE — Sun, 30 Oct 2011 04:03:39 GMT

From TR-3483:

"A FlexVol volume with a guarantee of “none” reserves no space from the aggregate

during volume creation. Space is first taken from the aggregate when data is actually written to

the volume. The example here shows how, in contrast to the example above with the volume

guarantee, the volume creation does not reduce used space in the aggregate. Even LUN

creation, which by default has space reservation enabled, does not reserve space out of the

aggregate. Write operations to space-reserved LUNs in a volume with guarantee=none will fail if

the containing aggregate does not have enough available space. LUN reservation assure that

the LUN has space in the volume but guarantee=none doesn’t assure that the volume has space

in the aggregate."

The LUN is space reserved by default, however you won't see the space subtracted from the aggregate if volume space guarantee is set to none.

Chaning the space guarantee to volume will be fine, as long as you have enough space in the containing aggregate.

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Is it possible to create a Space Reserved LUN in a volume without a Space Guarantee?

Is it possible to create a Space Reserved LUN in a volume without a Space Guarantee?