topic Re: Where is my free space? in ONTAP Discussions

Where is my free space?

Alexio — Wed, 04 Jun 2025 09:52:21 GMT

Hello everyone, I've a FAS2650 with about 72TB of total usable capacity. This is my df output:

Aggregate total used avail capacity

aggr_NFS_FAS2650_01 36TB 32TB 4131GB 89%

aggr_NFS_FAS2650_02 36TB 33TB 3247GB 91%

As you can see, I'm running out of space. I'm using this storage only for nfs volumes and no LUNs. I ran a "volume show-space" and summing all the entries "total physical used" I get 38.45TB so I should have about 33TB available but aggregates only shows about 7TB. I really can't figure out what I'm missing.

Thank you for your help.

Best,

Re: Where is my free space?

Ontapforrum — Mon, 06 Mar 2023 11:01:26 GMT

Are the volume(s) attribute set to 'guarantee' ?

A "guarantee" type of volume allocates space in the aggregate for the volume when you create the volume, regardless of whether that space is used for data yet. When you use thick provisioning, all of the space specified for the volume is allocated from the aggregate at volume creation time. The volume cannot run out of space before the amount of data it contains (including Snapshot copies) reaches the size of the volume. However, if your volumes are not very full, this comes at the cost of reduced storage utilization. When you use thick provisioning, all of the space specified for the volume is allocated from the aggregate at volume creation time. The volume cannot run out of space before the amount of data it contains (including Snapshot copies) reaches the size of the volume. However, if your volumes are not very full, this comes at the cost of reduced storage utilization.

Space Usage:
https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Software/ONTAP_OS/Space_Usage

Methods to create space in an local tier (aggregate):
https://docs.netapp.com/us-en/ontap/disks-aggregates/methods-create-space-aggregate-concept.html

How to reclaim space in an aggregate that is full? - NetApp Knowledge Base

Re: Where is my free space?

Alexio — Mon, 06 Mar 2023 11:17:43 GMT

I'm so sorry, I didn't notice it! All my volumes are "Thick Provisioned". Can I safely change them to "Thin", I obviously have enough space to do it. Thank you!

Re: Where is my free space?

Ontapforrum — Mon, 06 Mar 2023 11:27:03 GMT

Yes, it is absolutely safe. It's just a meta-data attribute change and can be done on the fly.

This kb covers this as well:

What is the impact of changing volume space-guarantee from "volume" to "none" - NetApp Knowledge Base