dRAID GUI Question: 1 additional drive is added to children

[shota]

Greeting,

I am learning how dRAID works.
Let’s assume I have 12 drives, and I want 1 vdevs of 4 drives.
I tried to setup one vdev has dRAID1 with 2 data drives, 1 parity drive, and 1 hot spare drive.
In this case, the number of children should be 4, but the WEB GUI says 5, as shown the figure below.

Could you help me understanding why an extra 1 drive is added to children?
Thank you very much for your help and kindness.

OS Version:TrueNAS-SCALE-24.10.0.2
Product:Super Server
Model:Intel(R) Xeon(R) Silver 4108 CPU @ 1.80GHz
Memory:124 GiB

Possibly related bug report

[shota]

By the way, the same issue occurs even if I increase the number of data drives.

dRAID1: 9 data drives, 1 hot spare = 12 children

dRAID1: 9 data drives, 2 hot spare = blank children (no option)but I can create a pool! (why???)

dRAID1: 10 data drives, 0 hot spare = 12 children

dRAID1: 10 data drives, 1 hot spare = blank children (no option) but I can create a pool! (why???)

[bacon]

Looks like a bug to me.

The code doesn’t make sense. It increments the label by one but not the actual value. It also doesn’t go from minimum children to maximum children:

      nextOptions = _.range(groupSize + hotSpares, maxPossibleWidth).map((item) => {
        const disks = item + 1;
        return {
          label: String(disks),
          value: disks,
        };
      });

Should be something more like this:

      nextOptions = _.range(groupSize + hotSpares, maxPossibleWidth+1).map((item) => {
        return {
          label: String(item),
          value: item,
        };
      });

[etorix]

File a bug report, with the suggestion.

[shota]

Filed a bug report as suggested.
https://ixsystems.atlassian.net/browse/NAS-132739

Thank you @bacon for your help and kindness.