Thanks for link. Firmware SC60 on all disks.
I checked all 3 Iron Wolf disks one by one and all 3 together, spin down and hibernation working fine if disks are installed to NAS and not added to raid.
I removed raid volume and created it again, to verify that issue is not related with ADM upgrade to latest version after initial setup of NAS.
Now I see Disk Activity in ADM Activity Monitor and "mdadm - Storage Management Tool - Read" on Volume1 (SSD disk) and Volume2 RAID in ADM Diagnostic Tool.
Previously everything was blank.
Now at least I see constant "mdadm, Storage Management Tools, Read" activity in ADM Diagnostic Tool on main Volume and RAID Volume . I will monitor for one more day as this is maybe RAID post creation activity. Lazy Init (Synchronization) is complete fully, no related messages in filessytem IO.
After restart same behavior of NAS (reading disk each minute, spinning down, up), no logs as previously in ADM Diagnostic Tool, Disk Activity in Process Monitor.
Looks like something is changed in log level during creating of volume and log level is set to previous level after restart.
Non Raid disk (same model, same firmware version) went sleep as expected in time defined in ADM.
Do you have any experience with Asustor support? How long it takes for reply Ticket and how professional are answers?