I would like to have a silent Server and therefore I would like to spin down my disks when I don’t need them. Luckily I use a nvme for all my virtual machine storage and an ssd for booting, which are practically silent.

For Longterm Storage I have 2 spinning SAS HDDs on a RAID controller.

Before I attempted to access my HDD I flashed my LSI Raid controller from IR to IT mode in oder to directly access the Harddrive.

This might not be necessary. You can try using sdparm instead of hdparm and see if you can access the disks behind your RAID controller without having the discs on JBOD mode (IT mode)

The important part is to deactivate any processes in Proxmox that regularly activate your spinning disks, otherwise they will spin up almost immediately after you spun them down.

pvestatd
smartd

Stop ProxMox Services from addressing the HDDS by adding them into filter lists

nano -4 /etc/lvm/lvm.conf

scroll to the very end of lvm.conf file

devices {
     # added by pve-manager to avoid scanning ZFS zvols and Ceph rbds
     # global_filter=["r|/dev/zd.*|","r|/dev/rbd.*|"]
     global_filter=["r|/dev/disk/by-label/backup_2.*|", "r|/dev/disk/by-label/backup_1.*|", "r|/dev/sda.*|", "r|/dev/zd.*|", "r|/dev/m>
}

nano cat /etc/smartd.conf

add this to your smartd configuration

# The word DEVICESCAN will cause any remaining lines in this
# configuration file to be ignored: it tells smartd to scan for all
# ATA and SCSI devices.  DEVICESCAN may be followed by any of the
# Directives listed below, which will be applied to all devices that
# are found.  Most users should comment out DEVICESCAN and explicitly
# list the devices that they wish to monitor.


/dev/sdb -d ignore
/dev/sdc -d ignore
/dev/sdd -d ignore

....

Example commands to spin down disks manually

sdparm --command=stop /dev/sdc

Unfortunately after spin down the disk doesn’t seem to wake up by itsself automatically when needed. I hope to be able to address this issue soon

The Next step would integrate these commands into a startup script or a cron schedule.

For People like may me, that only need to activate the slow spinning HDDs once a week for a backup it can be an option to script everything with cronjob. Otherwise having the disks wake up automatically everytime a service wants to use them is definetely a good thing to have.

Ressources:
HDD never spin down | Proxmox Support Forum
HDD never spin down | Page 2 | Proxmox Support Forum