I cleared the configuration through the boot_ontap menu (4. Clean configuration and initialize all disks) on a new FAS2720(9.7P7) and DS212C using a total of 24 NL-SAS disks (10TB). Now the root aggregates is installed on 12 whole disks.
The problem is that I can create only one single aggregate (RAID-TEC only because of the size of the disks) on the first controller and I can't create a second aggregate on the second controller because I don't have enough disks to do so.
I heard about ADP to reduce the number of disks on the root aggregate but I did not find something very clear about it.
In my opinion, the root aggregates are not installed on 12 Full drives but on partitions. On the FAS2720 the first 12 drives can be partitioned leading to 2 logical drives per physical one (Exemple: 1.0.1P1 and 1.0.1P2)
you could then create an aggregates for node X using the 10 other big partitions that will give you around 55TB (using raid tec, and 10 partitions)
Then you will be able to create another data aggregate using full drives that are in the external shelf that will give U an extra 56TB like in the following exhibit:
If you can't do it then can you share the following output:
set -d -c off;disk partitions show
That will help us understand the current situation