NSA325 v2 - post install questions (no replies)

Hi,
I successfully install the latest u-boot and rootfs (using an external SSD) on a NSA325. Thank you for your work!

I see on some tutorials the move/install of rootfs into HDD. Doesn't this prevent HDD to spin-down?
Also, using mdadm I can "recover" my old partition. Is it any technical reason to create from zero new partitions instead of using existing ones?
Did anyone using btrfs on these boxes see improved performances over mdadm? Does make sense to change from mdadm?

Thank you

cata@debian:~$ cat /etc/debian_version
12.12
cata@debian:~$ uname -a
Linux debian 6.17.7-kirkwood-tld-1 #1 Mon Nov  3 16:38:22 PST 2025 armv5tel GNU/Linux
cata@debian:~$ lsblk
NAME    MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
sda       8:0    0   2.7T  0 disk
|-sda1    8:1    0   487M  0 part
`-sda2    8:2    0   2.7T  0 part
  `-md0   9:0    0   2.7T  0 raid1
sdb       8:16   0   2.7T  0 disk
|-sdb1    8:17   0   487M  0 part
`-sdb2    8:18   0   2.7T  0 part
  `-md0   9:0    0   2.7T  0 raid1
sdc       8:32   0 119.2G  0 disk
`-sdc1    8:33   0 119.2G  0 part  /