Add new HDD in hardware Raid and ZFS

[StaLeWaR]

Hi All!

I have a raid 5 on the controller HP P212.
He now has 4 HDD 2 TB.

I want to add more drives for 2TB.

behave like ZFS?
If the array is now represented by a single device.

I would like to say something about what ZFS disk capacity increased?

and yet why in the "df -h" does not display normally?

Code:

[root@freenas] ~# df -h
Filesystem            Size    Used  Avail Capacity  Mounted on
/dev/ufs/FreeNASs2a    926M    654M    198M    77%    /
devfs                  1.0k    1.0k      0B  100%    /dev
/dev/md0              4.6M    3.8M    399k    91%    /etc
/dev/md1              823k    2.0k    756k    0%    /mnt
/dev/md2              149M    41M    96M    30%    /var
/dev/ufs/FreeNASs4      19M    3.8M    14M    21%    /data
vdata                  3.8T    2.2G    3.8T    0%    /mnt/vdata
vdata/DSPM              50G    3.8M    50G    0%    /mnt/vdata/DSPM
vdata/DSadmins        4.0T    274G    3.8T    7%    /mnt/vdata/DSadmins
vdata/DSarhive        3.9T    95G    3.8T    2%    /mnt/vdata/DSarhive
vdata/DSbackup        1.5T    868G    667G    57%    /mnt/vdata/DSbackup
vdata/DSbox            4.1T    356G    3.8T    9%    /mnt/vdata/DSbox
vdata/DSfolders        100G    22k    100G    0%    /mnt/vdata/DSfolders
vdata/DSpublic        100G    50G    49G    50%    /mnt/vdata/DSpublic
vdata/DSscans          50G    2.9G    47G    6%    /mnt/vdata/DSscans
vdata/jails            3.8T    33k    3.8T    0%    /mnt/vdata/jails
/dev/md3              1.9G    3.3M    1.7G    0%    /var/tmp/.cache
[root@freenas] ~# zpool get all
NAME  PROPERTY              VALUE                  SOURCE
vdata  size                  5.44T                  -
vdata  capacity              29%                    -
vdata  altroot                /mnt                  local
vdata  health                ONLINE                -
vdata  guid                  17972618758330237450  default
vdata  version                -                      default
vdata  bootfs                -                      default
vdata  delegation            on                    default
vdata  autoreplace            off                    default
vdata  cachefile              /data/zfs/zpool.cache  local
vdata  failmode              wait                  default
vdata  listsnapshots          off                    default
vdata  autoexpand            off                    default
vdata  dedupditto            0                      default
vdata  dedupratio            1.00x                  -
vdata  free                  3.83T                  -
vdata  allocated              1.61T                  -
vdata  readonly              off                    -
vdata  comment                -                      default
vdata  expandsize            0                      -
vdata  freeing                0                      default
vdata  feature@async_destroy  enabled                local
vdata  feature@empty_bpobj    active                local
vdata  feature@lz4_compress  enabled                local
[root@freenas] ~#