I've had a 7 drive system running for a while, 1x2TB parity, 5x2TB data, and a 1TB caviar black for cache. I ran out of space when there weren't any good deals on 2TB drives, so I turned the 1TB into a data drive as part of the array (now has roughly 400GB on it). I just got a new 2TB drive, and would like to swap that in for the data drive and reassign the 1TB as a cache drive. The server is mainly used to store movies, and transferring 30GB files goes quite a bit quicker with a cache drive.

 

I've never had to alter the disk structure of my server aside from adding new disk, but this is what I was thinking:

 

1- preclear new drive

2 - stop server

3 - move files from 1TB caviar black to new 2TB with mv command

4 - start server, unassign 1TB caviar black from array and assign new 2TB

 

At that point, I'm not quite sure what will happen. All the same data is present, but it's on a different drive, so will I need to rebuild the parity drive? Anything to watch out for? Thanks in advance!

If it were me, I'd do it like this.

1. Preclear new drive for 2 or 3 cycles, enough to trust it isn't going to fail in infancy.

2. While that's happening, run a non-correcting parity check with unmenu, probably a couple, since step 1 is going to take a long time.

3. Stop array, unassign 1TB from array, immediately assign freshly precleared 2TB to same slot.

4. Start array, allow unraid to rebuild and expand to new drive.

5. After step 4 completes successfully, preclear 1TB once just to be sure it's still healthy, and clear it out.

6. Assign 1TB as cache drive.

7. Profit???

 

There is no need to manually move files, just let unraid reconstruct the contents onto the new drive. As long as you are confident all your other drives are good, it should be a no stress operation.