Writes fail when Logical Space used hit volume physical max size

ONTAP 9

The error message: Mon Sep 27 15:50:40 +0200 [exonet-netapp-c3-01: wafl_spcd_main:monitor.vol.nearFull.inc.sav:alert]: Volume vol1@vserver:vserver1 (UUID 856709fa-6a1b-11eb-9afb-d039ea140bb7) is nearly full (reserved or using 97%% of space including savings and 0%% of inodes is being returned.
The values for the used volume in Linux and Netapp are different: this difference is equal to the value for total-savings from Storage Efficiency.

Example:

The used volume in Linux is 9TB:

Filesystem Size Used Avail Use% Mounted on

10.10.10.10:/vol1 12T 9T 3T 75% /vol1

Whereas the physical space value is 6TB:

Vserver Volume Aggregate State Type Size Available Used%

--------- ------------ ------------ ---------- ---- ---------- ---------- -----

vserver1 vol1 aggr1 online RW 12TB 6TB 50%

The volume saved through storage efficiency features is equal to 3TB:

Filesystem Used Total-saved %total-saved deduplicate %deduplicated compressed %compressed

/vol/vol1/ 5693065812 3221225472 35% 3221225472 35% 0 0%