HDD lights keep flashing while unit idle

Hi There,
I have a TS-464 with 2 x 4tb drives which are working fine except that the HDD lights and the yellow/orange light intermittently flash while in idle with no actions being taken.
Can you please advise why this is happening please?
Thanks in advance

Rodger

I feel it is normal because some slight IO may still happen when the system is doing background tasks.

For example, even if you’re not actively using it, the NAS may

Check Disk Health: Regular SMART checks or monitoring.
Index Files: Making thumbnails for example.
Run System Tasks: Like RAID synchronization or cleaning up logs.
Network Activity: Check system/package updates or background services.

These are supposed to be normal and help keep the NAS running smoothly.
You may check Resource Monitor to see the disk usage as reference as well.

you could also see what is accessing/running on your NAS here:

you may not want your NAS to sleep, however it may give an indication on what’s active.