Bad Block Scan multiple drives simultaneously?

[Boston_Photog]

Hi,

Apologies if this has been asked and answered before, but I searched and couldn't find an answer.
I have a TS-412 with four 3TB drives installed in a RAID5 configuration. This is a new NAS that does not yet have any data on it. I wanted to do an initial bad blocks scan so that when I write data to the array the NAS would not write any data to bad blocks (the unit has this functionality, right? It will avoid writing data to bad blocks if it is aware that they exist?).

In any case, I know that will 3TB drives, doing this bad block scan will take a LONG time. I am wondering, can I do the scan on all four drives simultaneously? Will attempting to do so cause problems?
Also, will doing the scan on all four drives at the same time take less time than doing the scan on one drive at a time? In other words, is the unit capable of scanning more than one drive at a time, or will it simply slow down the scan of each individual drive and end up taking the same amount of time if I had done them individually?

Thanks very much for the help.

Sincerely,

Boston_Photog