Drive Size Order?

You are using jbod I think? If so, you'd back up the 500 GB volume, then delete it and remove the drive. Then put in the new drive in the same slot and create a new volume / restore the data.

I suggest searching the forum for your drive model before purchase - there are some drives on the HCL that don't seem to have worked out so well.

StephenB wrote:
You are using jbod I think?

What is 'jbod'?

I have checked the HCL; and my choice is between WD Red WD30EFRX or Seagate Barracuda ST3000DM001.

Is it possible to replace the 500Gb drive with my existing 2Tb drive in bay 1...

...and then insert the new 3Tb drive in bay 2, so that the data in drive 1 automatically mirrors to the new 3Tb drive in bay 2?

JBOD: "Just a Bunch Of Disks"; an array of drives, each of which is accessed directly as an independent drive

You have two mismatched drives now (500 GB and 2 TB). Are you using XRAID-2 (giving you a single 500 GB volume), or do you have two volumes (one 500 GB and one that is either 1.5 TB or 2 TB)???

Basically you can
(a) forget about RAID and create 5 TB total storage space (not redundant at all)
(b) Use XRAID2 and get 2 TB total storage space (wasting 1 TB, but fully redundant)
(c) Use FlexRAID and get 2 TB of redundant RAID-1 storage, and 1 TB of additional non-redundant space

Picking (a), (b) or (c) is the first choice. How you migrate your data will depend on what you chose, and what you have now.

BTW, personally, I recommend the WD30EFRX over the ST3000DM001. Either way, search the forum for other user experiences, don't just pick something off the HCL.

I am using X-Raid...

Originally, I had 2 x 500Gb drives in my original DUO.v1, and then 'upgraded' one of the disks to Seagate 2Tb LP (with the plan to buy another 2Tb).

Then, I changed to the NV+v.2, and in the meantime disk sizes have got larger.

So, rather than just buy another 2Tb drive to replace the 500Gb drive I thought I might as well go for the 3Tb drive instead (and buy another later when I can afford it).

I still want X-Raid functionality, though.

Somehow, I want to retain all my existing data, but with the 2Tb drive in bay 1 and the 3Tb drive in bay 2 (and I appreciate that 1Tb of the 3TB disk will be 'wasted').

It doesn't look as though this is achievable in a simple manner?

If there is a simple way to achieve this I would be grateful for your advice.

If you are using XRAID2 now in your V2, then all you need to do is remove disk 1, and insert the new 3 TB drive into that slot. Do all that with the NAS running. More than likely the NAS will ask you to reboot it after a while to continue with the expansion.

You'll end up with the 3 TB drive in the first slot, but that doesn't matter. If you are determined to swap them, you can try that at the end (with the NAS powered off).

You should do a backup first of course (at least keep the 500 GB drive intact until the expansion is complete.)

I thought that the lower capacity drive had be inserted in bay 1 (the 2Tb disk), with the 3Tb in bay 2.

You seem to be suggesting that the 3Tb drive would be inserted in bay 1, with the existing 2Tb drive remaining in bay 2.

What is important is that smallest drives are installed first. The NAS is smart enough to handle higher capacity disks being in different bays. If the drive in bay 1 is the drive you are replacing then you should put the replacement drive in bay 1

So, with my existing 500Gb drive in bay 1 and my existing 2Tb drive in bay 2...

Initially, I will replace my existing 2Tb drive in bay 2 with a new 3Tb drive in bay 2, and allow resync to complete.

Then, I would swap the 500Gb with the 2Tb drive in bay 1.

In so doing, the 3Tb drive in bay 2 will then resync it's data with the 2Tb drive in bay 1.

Is this the correct procedure?

It should work but it is much harder than it needs to be - and therefore creates more opportunity for something to go wrong.

I gave you the procedure above - remove the 500 GB drive with the NAS running, and then insert the 3 TB drive in the same slot.

There is no need to do anything more, and there is no advantage in arranging things so the 2 TB disk is in slot 1.

mdgm told you the same thing. "smallest drives inserted first" means first in time, not first in slot order.

StephenB wrote:
"smallest drives inserted first" means first in time, not first in slot order.

Thanks: that's what I needed to know (I had previously believed that it was in slot order).

So I should end up with mirrored 2 x 2Tb capacity (with 1Tb being redundant on the 3Tb drive).