TD2 Raid1 orange light

[iPadawan]

After i replaced the internal drives with two WD 4TB drives, a;ter setting the switch at Raid1 and reset the box, I could initialize the volume.
Copy data on it, around 1.5TB, both the disk lights where green and as far as I could see they never gets orange.
However after finishing the copy task, the lower disk led light start flashing orange and most of the time equally with the upper green light.
It is doing for more then 30 hours; why? Is it doing block synchronizing ?

The disks where tested and no smart errorr or whatsoever.

Any suggestion?
Is there a Mac terminal command or app that i can look into the RD2 and see what is going on?

[iPadawan]

Of course it is TD2 instead of RD2

[TMzethar]

Normally, data is written to both disks at the same time when you copy the data.
The orange light that appears after that is probably because the disk was taken out of RAID1 and synchronization was initiated when it was reconnected.
If you did not experience similar problem with the previous disks, perhaps you should consider checking the condition of this hard disk show orange.

[iPadawan]

Thank you for comming back to me.

However, it is running for 35+ hours now. Stil ‘not’ finished with doing something; both drives are busy.
The disk where fine and tested.
I did not remove the disk.

[TMzethar]

Hi, what's the status of the TD2's lights and capacity now? Is it working properly?
We've noticed an unusual operation.
TD2 does not support capacity expansion, even if you replace two 1.5TB with two 4TB.
Generally speaking, the final capacity does not increase.