Hallo Mida,
vielleicht gibt es auch im dst eine andere Sicht und ist denn
eigentlich das Ptf Mf33511 installiert ?

Die Alternative:
RAID 6 parity set
The minimum number of disk units in a parity set is 4. The maximum number of disk units in a parity set is 18.

To learn more about how device parity protection is implemented, see How device parity protection works. Examples: Device parity and mirrored protection shows some examples of how device parity protection can be used in conjunction with mirrored protection.

Start device parity protection
In iSeries™ Navigator, expand Disk Units.
Select the disk units for which you want to start device parity protection.
Right-click a selected disk unit and select Start Parity.
Select the level of RAID protection you want.
From the resulting window, click Start Parity to start device parity protection on the displayed disk units.