ONTAP Discussions

How to create Root aggregate across external shelf during initialization


Hi everyone,
First time posting here.

On a new FAS2720(9.5P5) and DS212C, I would like to configure ADP using a total of 24 NL-SAS disks.
So, I actually executed the steps 9a and 9b from the boot menu, but a Kernel Panic occurred after executing step 9b.
When a Kernel Panic occured, the following message was displayed.

Jun 27 17:48:57 [localhost: raid.autoPart.start: notice]: System has started auto-partitioning 6 disks.
Jun 27 17:48:58 [localhost: raid.autoPart.done: notice]: Successfully auto-partitioned 6 of 6 disks.
Unable to create root aggregate: 5 disks specified, but at least 7 disks are required for raid_tec

According to HWU, FAS2720 can configure ADP with 24 disks.
Is this due to a bug in the product? Or is there any problem with the procedure?

As a side note, I think that it is a problem that occurs only when an external shelf is connected,
because there is no problem in performing the same procedure without connecting DS212C.


Could you please help?
Many thanks



Hi, and oops. Sry for using german.


I today hit the same issue with a FAS2720 with 8 TB SATA ( 9.5P8 ). Used the 24 disks approach. Solved the issue for me. The new root aggregates are created with raid_dp and using 5 Disks, which is pretty odd, the error messages given. Think about a bug as well. Have logs with me and will try to file case as soon as I find any time for it. Will update accordingly.

best regards



Regarding this comment:

    3. As you noted, if you expand a RG with partitions, spare whole disks will be automatically partitioned. That said, you would avoid the wasted P1 partition "tax" if you simply created a new RG with your external shelf drives as whole disks.


Not always the best in this case. Why? If I have 11 or 12 partitioned disks (using RAID-TEC), This should be something like 7d+3p+1s  or 8d+3p+1s or 7d+3p+2s. In all cases, RAID-TEC is using 3 parity drives. If I create another Raid Group (of say 8d+3p+1s), it will consume 3 more parity drives (30TB). If I just expand the RAID-group and let the system partition, the worst case you are losing 100GB per disk for the root partition (that would be up to 1200GB which is much better than 30TB).


Exceptions to everything, right? If I have more than an extra shelf, then I would have to consider what happens as I expand and do I plan to add more in the furture. i.e. Do I want the Parity tax now (ad be able to add drives later with no potential partity needed) or just add the parity later?



For opt9a/b  try and  park/halt the partner node while youre working on the other one.   


1 Park Controller 2 at LOADER-B>
2 Boot Controller 1 in to the boot menu and do opt 9
a Run opt 9a
b Run opt 9b
3 Wait for the init  to finish on Controller 1 and halt to LOADER-A>
4 Boot Controller2 in to the boot menu
a Run opt 9a
b Run opt 9b
5 Wait for Controller 2 to finish.

Boot into ontap and check "storage disk show -partition-ownership"