ISSUE

I have a Dell PowerEdge r720 rack-mounted server.  The server has 4 drives and the raid has been set up as a RAID 6.

While on a site visit, I was told that one drive went bad and needed replacing.  

- The Tier 1 techs had already pulled out the bad drive before i arrived (Disk 1).  

- Upon arrival, I inserted a new drive into Disk 1.  The drive started to blink fast and appeared to automatically be rebuilding.  I also noticed they other disk were all fast blinking green (0,1,3).   Disk 2 stayed solid green.

- Next morning, i rebooted the server and entered the Raid controller BIOS.  I then found that the raid was in a degraded status and that Disk 2 was in a "Foreign" State.

At present, disk 0,1,3 are in a RAID 6, however disk 2 is in a "Foreign" State.  My assumption is that the Tier 1 support pulled disk 2 out and may have tried to swap with disk 1..   Or at the very least they pulled out disk 2 - which is causing the foreign configuration state.   

I have reviewed the foreign configuration and it is what they had before to the best of my knowledge, but i am not certain that DISK 2 and Disk 1 are in the original positions. 

QUESTIONS

1.  What will be the impact if i clear the foreign state of disk 2?  Also, once the disk goes to "Ready" state, is it possible to bring Disk 2 back into the VD that is already created.

2. What will be the impact if i import the foreign state of disk 2 and the disks are not in the exact same position as before?

Thank you all for your responses.

Lawrence