HDDs starts automaticaly every 20min from standby

Hi, my problem is, my HDDs starts automaticaly every 20min from idle/standby. -

  • There is no internet connection available (cable is disconnected),
  • the only app (Jellyfin) was stopped manually,
  • System Dataset Pool:boot-pool’,
  • TrueNAS is located on a dedicated SSD.
  • it concerns a pool with 3 HDDs + NVME Cache,
  • also I have one NVME for App Space.
    What can I do to prevent?