Actually I did exactly this about 2 weeks ago... I had one of my DNS-343 fail to boot, it was hanging at "system is booting...". To make sure my data was fine, I took a spare DNS-343 which I hadn't gotten around to configuring yet, upgraded it's firmware to make sure it was on the same level as the dead one, and then transfered the drives over (assuring to keep in the same order).
Booted up and I was pleasantly surprised to see that all my data was safe, and all worked like a charm.
One thing however is that both my units were purchased at the same time and were pretty identical.
The replacement I just received seems to be from a different batch.. Even the MAC address of the ethernet controller is completely a different series..
Both of my old units were 00:26:5a:xx:xx:xx but the new unit which was shipped to me is 1c:af:f7:xx:xx:xx. 00:26:5a:xx:xx:xx is a registered prefix for "
D-Link Corporation" and 1c:af:f7:xx:xx:xx is for "
D-LINK INTERNATIONAL PTE LIMITED". Not sure if this difference will make a difference in the success of transferring disks.
With the new unit i recieved, i tried using a set of spare disks which I had used on my old unit, but I had to physcially do a quick sector erase (I used the WD Diag software which I had installed on my PC) since otherwise the new DNS-343 would hang on boot..
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I don't know if this is because my old unit had corrupted these disks (since this was the set I used to try all sorts of things to revive the defective unit - didn't want to risk my data on my other set), was it because of h/w differences, just a coincidence, or did I accidently put them in wrong order...
Good luck, hope it helps..