Hi @wolfkiler ,
I assume that you are asking about how to check the SAS ports available to add a new disk shelf stack to NetApp ONTAP based storage.
If so you can use the command "storage port show" this will list the SAS ports and those shown as "enabled" and "offline" are available for use.
There is some doco here: https://docs.netapp.com/us-en/ontap-cli-9141//storage-port-show.html
An Example of an AFFA300 that has one shelf stack connected is as below:
cluster1::> storage port show
Speed
Node Port Type (Gb/s) State Status
------------------ ---- ---- ------ -------- ---------------
node1
0a SAS 12 enabled online
0b SAS 0 enabled offline
0c SAS 0 enabled offline
0d SAS 12 enabled online
node2
0a SAS 12 enabled online
0b SAS 0 enabled offline
0c SAS 0 enabled offline
0d SAS 12 enabled online