Best / quickest / least painful way to “vertically” expand a NAS when having a full data backup

Update again – plus some kind of snag  😞

I created the 2x12TB + 2x4TB array as planned, went through the single double-resyinch (2x ~36h), upgraded FW and everything worked out perfectly fine.

After copying all the data which was on the NAS original array, I copy-moved there all the data which was scattered around on various 4TB USB drives, other disks on another PC, and the RN424.

Then I started consolidating the dataset moving all various folders in a more organised manner.

This is when I realised that - guess what, I was running out of space on the new array.

I initially panicked, thinking that I had misconfigured the lot and created like 5TB of snapshots (like it happened before, some while ago); (only at that moment I realised - it hadn’t occurred to me before - that the snapshots are created for an entire share and not a subfolder).

So, thinking that the share where I moved the data had enabled snapshots, I created another share, made sure that snapshots were not going to be created there and started moving data in this new share (using the web interface, which I am not familiar with – infact it was probably the FIRST files/folder movement I ever done using it).

Few minutes later I realised that ACTUALLY, I had only 32 GB of snapshots in total in the entire array, and they were in some other shares, so that was NOT why I was running out of space

So I reasoned that, obviously, I did not do my sums right in the first place and underestimated the space I needed (well, I was never running out of space, but I would have ended up with three NASses which would have been 75/80% full, and I would have never had the space to start having some proper backups etc.).

So I decided to get the other 2x 12TB and create the full, proper array. I stopped all that moving to the new share operation, as it was unnecessary at this moment, and started moving the data OFF the new 214a array to the old locations, so I could scrap the new array entirely, create a new one directly with 4x12TB and save all that double resyinching exercise (2x2 resynchs of 36h would have been lengthly...).

This morning I got the 2x 12TB SG IronWolf, from the same “official” (3y warranty) retailer I bought the first couple, planning to ReadWriteVerify test them as soon as possible, and started looking of where to move the data, according to where I had the space, wishing to avoid the USB disks etc.

It was only then that I realised that – SHOCK HORROR – I have lost data, and a conspicuous amount too, ~2.5TB (in one dataset, three years of data, 2018, 2019, 2020 have disappeared entirely and 700GB from the 2021 folder are missing).

And of course I don’t have any snaphots, that folder was (properly, lol) configured NOT to have snapshots.

Of course, if the data was on a normal disk, there are plenty of programs which would allow me to undelete/recover the data. But on a RAID… well, I know that there a few programs which can reconstruct failed/corrupt array (never been able to recover any data with the shareware versions, tho’), but this is a different situation, the array is (presumably) not corrupt, I simply cancelled/aborted the “moving” operation without realising that ONLY the data which had been transferred would have survived (if this is what happened). This is why one should have a snapshots/backup policy in place.

At moment I am moving data out of the array. That may take over a day or two if not more. I am also testing the new disks, circa 30h remaining.

Once all the (transferred) data has been moved back, since I still have the original full backup of the data which was on the 214a before doing anything, I could do a factory default start from scratch again. Unless there is a way to recover those lost subfolders, that is.

Incidentally, all the data which has been lost came out of the RN424, and I am not moving any data there yet (but I might have written ~100GB of new data in the last few days). Needless to say, there are no snapshots, but 5.1TB of free space, ~25%. If I wish to leave that space alone, I have the 3x 4TB disks which were de-commissioned from the 214a which could be wiped clean if necessary; I also have 3.3TB free-able on a PC and ~2.95TB  on an USB.