On the 800 platform, drives are automatically assigned based on position in the shelf. The drives are then automatically partitioned...the owner of the disk gets Partition 3 (root). Each node in the ha-pair gets a data partition (Partition 1 and Partition 2 are both Data partitions and they are assigned based on serial number)
If I have 18 drives in a C800, I expect to have:
9 drives owned by node 1 (9 root partitions for node 1, 18 data partitions owned by node 1)
9 drives owned by node 2 (9 root partitions for node 2, 18 data partitions owned by node 2)
When you make an aggregate, just be sure leave enough spare partitions
aggregate create -node node-01 -diskcount 17 -aggregate cnvme_01 -maxraidsize 24
This creates an aggregagte on node-01 using 17 partitions and leaving one spare
Review the output:
storage aggregate show-spare-disks
You will see which nodes have which partitions free