Replacing a drive and adding a drive - best method?

[flips]

I’m looking for some advice.  I have waffled back and forth and I would like to get some advice from other users.  I searched, but I couldn’t find a good answer, probably because this is a pretty specific case…  I did see both sides of a similar issue in this thread:

http://lime-technology.com/forum/index.php?topic=20510

 

I have a drive that has two smart categories above the threshold (but has been stable and working well) and is still under warranty, so I got a warranty replacement drive.  I also have another drive that that I want to add to the array after I upgraded my parity drive to 4TB.  Both drives are pre-cleared.  Should I:

 

1.) Replace the bad drive with the new drive and then let parity rebuild?  Then add the additional drive to expand the array?

2.) Do I expand the array with the new drive and copy (or move) all the files over to the new drive, then replace the now empty drive and let parity rebuild?

 

I see advantages of both options.  On option 2, if I copy all the files over will I have issues with the same files on both drives that is part of a user share, do I copy to a non-user share, and then move?  Do I do a verification (not sure how) after copy?  Or should I make some sort of a md5 check sum on all the files and then do a compare after option 1 before I preclear the drive and send it back to WD?  For option 1 I would back up the config dir so I can always drop back to the old config if something goes wrong.  This is my first drive replacement on unraid (thankful for that), so I am a bit nervous..  hence all my waffling and hand wringing.

 

Thanks for the advice,

flips

 

[garycase]

There are several approaches you could take ... a parity-swap;  a parity upgrade, followed by a rebuild; etc.

 

If your replacement drive is the same size as the failing drive (so there are no size issues with a rebuild), I would do the following:

 

(a)  Do a correcting parity check and confirm there are no sync errors.

(b)  Replace the failing drive and let the system do the rebuild.  Then do another parity check to confirm all went well.

©  Replace your parity drive with the 4TB unit and let it rebuild

(d)  Now add your new drive(s)