Por que o pool do ZFS mostra diferentes 'Tamanho' x 'Tamanho no disco'

Question

Então eu tenho uma unidade compartilhada (chamada 'Share_Drive') em um servidor Ubuntu. A pasta é compartilhada publicamente na minha rede em casa.
Os dois discos estão em um pool espelhado do ZFS:
MasnoteinoWindows,pastasnaunidadederedeestãomostrandoumestranho'tamanhoemvalordedisco'.Euesperariaqueelemostrasseodobrodovalorde'Tamanho',masessenãoéocaso.AbaixoestáumapastadeumbackupdePCqueé~1,53vezesotamanhodovalordapasta.
Esse é um caso de o Windows ler de maneira incorreta o tamanho real da pasta ou algo que eu configurei errado com o pool espelhado?

Editar
zfs pega tudo:

NAME         PROPERTY              VALUE                  SOURCE
Share_Drive  type                  filesystem             -
Share_Drive  creation              Wed Jul 12 20:22 2017  -
Share_Drive  used                  1.57T                  -
Share_Drive  available             194G                   -
Share_Drive  referenced            1.57T                  -
Share_Drive  compressratio         1.00x                  -
Share_Drive  mounted               yes                    -
Share_Drive  quota                 none                   default
Share_Drive  reservation           none                   default
Share_Drive  recordsize            128K                   default
Share_Drive  mountpoint            /Share_Drive           default
Share_Drive  sharenfs              off                    default
Share_Drive  checksum              on                     default
Share_Drive  compression           off                    default
Share_Drive  atime                 on                     default
Share_Drive  devices               on                     default
Share_Drive  exec                  on                     default
Share_Drive  setuid                on                     default
Share_Drive  readonly              off                    default
Share_Drive  zoned                 off                    default
Share_Drive  snapdir               hidden                 default
Share_Drive  aclinherit            restricted             default
Share_Drive  canmount              on                     default
Share_Drive  xattr                 on                     default
Share_Drive  copies                1                      default
Share_Drive  version               5                      -
Share_Drive  utf8only              off                    -
Share_Drive  normalization         none                   -
Share_Drive  casesensitivity       sensitive              -
Share_Drive  vscan                 off                    default
Share_Drive  nbmand                off                    default
Share_Drive  sharesmb              off                    default
Share_Drive  refquota              none                   default
Share_Drive  refreservation        none                   default
Share_Drive  primarycache          all                    default
Share_Drive  secondarycache        all                    default
Share_Drive  usedbysnapshots       0                      -
Share_Drive  usedbydataset         1.57T                  -
Share_Drive  usedbychildren        3.21M                  -
Share_Drive  usedbyrefreservation  0                      -
Share_Drive  logbias               latency                default
Share_Drive  dedup                 off                    default
Share_Drive  mlslabel              none                   default
Share_Drive  sync                  standard               default
Share_Drive  refcompressratio      1.00x                  -
Share_Drive  written               1.57T                  -
Share_Drive  logicalused           1.57T                  -
Share_Drive  logicalreferenced     1.57T                  -
Share_Drive  filesystem_limit      none                   default
Share_Drive  snapshot_limit        none                   default
Share_Drive  filesystem_count      none                   default
Share_Drive  snapshot_count        none                   default
Share_Drive  snapdev               hidden                 default
Share_Drive  acltype               off                    default
Share_Drive  context               none                   default
Share_Drive  fscontext             none                   default
Share_Drive  defcontext            none                   default
Share_Drive  rootcontext           none                   default
Share_Drive  relatime              off                    default
Share_Drive  redundant_metadata    all                    default
Share_Drive  overlay               off                    default