Configuring question

[teddy]

I am adding several disks to a Raid 5 and every time I add a disk it gets the message "configuring" which in my case takes more than 3 days to finish. Once it has finished, the synchronizing step begins, which takes around 12 hours to finish.
My question is, what is the "configuring" step doing to take so long?
Regards

[TMgevin]

Adding a hard drive will synchronize the data in the array, and the synchronization speed depends on the hard drive.

[teddy]

Thank you for your answer, but I have always understood what you told me to be the "synchronization" step that costs about 12 hours.
But the previous "confguring" step that was my question, it takes 3 days, what is it doing?

[teddy]

Is there any update about my question?