What is the difference between volume size and file system SSD storage in FSx for ONTAP?

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I'm able to provision an Amazon FSx for NetApp ONTAP volume larger than the size of the file system. What's the difference between the volume size and the file system SSD storage? How can I check the size of these on my file system?

Short description

After creating a new FSx for ONTAP volume, you might notice a difference between the file system size and the available space on the volume. The following are examples of these differences:

  • You created a new FSx for ONTAP 1 TB volume, but only see 500 GB of available space on the volume.
  • You have a 5TB Amazon FSx file system with 35 TB of volume. Initially, the volume size was 25 TB but was updated to 35 TB because of space issues.

These discrepancies might occur due to thin or thick provisioning.

FSx for NetApp ONTAP volumes created using the Amazon FSx console or the AWS Command Line Interface (AWS CLI) are thin provisioned. Volumes created using NetApp ONTAP CLI are thin provisioned by default. However, you can create thick provisioned volumes using the -space-slo thick command. In the following example command, replace SVM_name and volume_name with the correct values for your use case.

> volume create -vserver SVM_name -volume volume_name -aggregate aggr1 -size 10G -space-slo thick


Check the SSD storage

In an FSx for ONTAP file system, the SSD storage provisioned for the volumes is called an aggregate. The aggregate is a collection of disks arranged in multiple RAID groups. Use the df -A -h command to check the SSD storage space available in your file system:

> df -A -h
Aggregate                total       used      avail capacity
                         117GB       74GB       43GB      63%
                        6349MB       20KB     6349MB       0%
                         117GB       73GB       44GB      62%
                        6349MB       20KB     6349MB       0%
aggr1                    861GB     8165MB      853GB       1%
aggr1/.snapshot           45GB       20KB       45GB       0%
6 entries were displayed.

Note: FSx for ONTAP file systems require root aggregate for file system management. Root aggregate in FSx for ONTAP starts with aggr0, which isn't available for user data storage. The root aggregate aggr1 is the user data aggregate where the customer volumes are provisioned and data is stored.

Check the volume storage

Use the df -h command to check the volume size:

> df -h
Filesystem               total       used      avail capacity  Mounted on                 Vserver
/vol/vol_kumo/          9728GB      344KB      853GB       0%  /vol_kumo                  test_qtree
/vol/vol_kumo/.snapshot  512GB         0B      512GB       0%  /vol_kumo/.snapshot        test_qtree

In the preceding example, the volume vol_kumo is 9.7 TB and the available size is 853 GB. 853 GB equals the available aggregate size shown for aggr1.

If the SSD storage is full you can increase the file system or SSD size.

Note: You can't decrease a file system's size. Instead, you must create a new file system with a smaller size.

Additional commands you can use the verify the space used at the aggregate and the volume at a more granular level.

> aggr show-space aggr1
> volume show-space <volume name>

Related information

Managing FSx for ONTAP volumes

Configure volume provisioning options on the NetApp website

FAQ: Over-provisioning aka thin provisioning in ONTAP on the NetApp Knowledge Base

AWS OFFICIALUpdated a year ago