zpool free vs df -h

[KernelPanic]

Just when I think I have Freenas all worked out, ran into a full disk situation today...
What's the difference between zpool list and df -h

zpool list showed TB's free in the pool, but df -h showed 0.

Code:

NAME           SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
SSD           12.7T  7.98T  4.70T        -         -    41%    62%  1.00x  ONLINE  /mnt

Code:

root@psfs[~]# df -h
Filesystem                                              Size    Used   Avail Capacity  Mounted on
SSD                                                     2.3T     96K    2.3T     0%    /mnt/SSD
......

How does the pool have 4.7T free, but the Filesystem only get 2.3T free? It has no quota, and all folders below SSD all show the same 2.3T free.

So why am I missing 2.4TB? What have I missed?

Code:

root@psfs[~]# zpool status SSD
  pool: SSD
 state: ONLINE
  scan: scrub repaired 0 in 0 days 13:03:57 with 0 errors on Sun Nov 10 13:03:58 2019
config:

        NAME                                            STATE     READ WRITE CKSUM
        SSD                                             ONLINE       0     0     0
          mirror-0                                      ONLINE       0     0     0
            gptid/1504f3f8-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
            gptid/1596570f-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
          mirror-1                                      ONLINE       0     0     0
            gptid/161ea806-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
            gptid/16b214ac-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
          mirror-2                                      ONLINE       0     0     0
            gptid/175991ec-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
            gptid/17ee59ae-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
          mirror-3                                      ONLINE       0     0     0
            gptid/185d0a87-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
            gptid/18f15e92-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
          mirror-4                                      ONLINE       0     0     0
            gptid/1963bc3b-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
            gptid/19d1751f-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
          mirror-5                                      ONLINE       0     0     0
            gptid/1a4683f0-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
            gptid/1aca720c-be3d-11e9-8dff-002590847656  ONLINE       0     0     0
          mirror-6                                      ONLINE       0     0     0
            gptid/ab18b3c0-e5dd-11e9-ad2d-0cc47a183950  ONLINE       0     0     0
            gptid/abb0caae-e5dd-11e9-ad2d-0cc47a183950  ONLINE       0     0     0

errors: No known data errors

 

[colmconn]

Do you have snapshots enabled? If so, they will contribute to the data usage reported by zpool