ReadyNAS 314 showed "No IP Address", but got healed in a strange way

[el_patron]

I had a strange experience with my RN314, leading me to the question: what data is the CMOS battery keeping..?

One day out of sudden, after years of painless operation, the RN314 wasn't reachable and showed "No IP address".

Nothing helped:

• change the LAN port
• powering down and back again
• tried with Raidar
• changing again the LAN ports
• do a factory reset with a spare disk
• tried with Raidar
• changing the LAN ports
• ...

As nothing helped, I disassembled the unit, had a look on the main board PCB. There was absolutely nothing to recognize. I pulled out the CMOS battery and checked its voltage. As it was above 3V, I put back again.

I reassembled the unit and powered it. It booted up and immediately got an IP address and is back again working for some days now without further problems.

Any explanations by the experts..?

[StephenB]

AFAIK the battery itself just powers the real time clock (RTC).

Disassembling the unit would have involved fully disconnecting it from the mains - which might have cleared out something in the bios state.  So just guessing here, but I suspect it was cured by pulling the plug (instead of just powering it down).

[Sandshark]

The NIC is powered by a backup voltage generated in the unit from the input 12V that does not turn off when the NAS is off (so as to allow WoL).  So, it is possible that disconnecting from power long enough for capacitors to discharge "kick started" that circuit.  The power-on circuit is also powered by that voltage.  Did you notice anything odd about powering on and off?

If that is the root cause, I suspect it won't be a permanent fix, but is a sign of impending doom. 

[el_patron]

Before I disassembled it, it was quite a while powered off and disconnected, maybe a week.

I did not notice anything strange in powering on and off, but the unit was on all the years and only very rarely powered down, maybe for firmware upgrades or when I was for a longer time on vacation abroad.

When I put power back, the unit booted normally.

My trust in the reliability of the unit is somehow limited now...

[Sandshark]

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@el_patron wrote:

My trust in the reliability of the unit is somehow limited now...

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Until proven otherwise (and I don't know how you would), that is your best stance.  Extra care to assure your backup stays in order is the first priority, and insure it's in a format that you can get to files without the NAS in the interri before a replacement is procured as well as after.  Budgeting and assessment of need (is it time for a bigger/faster one?) for eventual replacement is next.