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[RobertSteed]

My DNS-320 was working last night but today it has suddenly broken. When it is switched on, the blue light flickers indefinitely and the NAS never starts - cannot be connected to via the web interface nor shares. Does this mean the NAS is done for, or is there some way to fix it? If not, how can I get the data off the HDDs which were mounted as a RAID array? Can an existing RAID array be imported into a PC?

[ivan]

First thing to do is find/borrow another power supply with an output of 12 volts at 4 Amps and use that to power your unit. the fact that the LED indicator is flickering points to a power supply that is not supplying full voltage (one of the capacitors in the PS partly breaks down and it no longer supplies full voltage under load).

If doing that brings your unit back to life the next thing you should do is make a backup of your data.

If your unit is still dead then it might be possible to recover your data depending on which RAID setup you used, RAID 0, RAID 1 or JBOD.  Of those RAID 1 is the easiest to recover data from while the other two require specialist software to do so.  There are details on what to do on the forum.

[RobertSteed]

Thanks for that. That might explain why the fan doesn't start. I tried a generic multi adapter set to 12 volts, with the same result, but then it has much lower ampage than required.

[ivan]

The Amps are critical.  With most adapters if you try to pull more current than it is rated for either the volts drop to try and compensate or, in well designed units, they shut down.

[RobertSteed]

I bought a new replacement PSU from eBay, which was advertised as specifically for the DNS-320. It says on the PSU that it's 5A. I still have the same problem . Should I conclude that the NAS has expired?

[ivan]

If that is the case then it COULD be.  I said could because there might be something as simple as a dry joint or a blown diode or resistor (we have even seen a faulty capacitor that produced a fault similar to the one you have).

The problem you have is two fold,
1) the unit requires someone with electronic expertise to look at it and confirm it is beyond repair and that costs money.
2) you need to get your data off your disks.  the ease of doing that depends on what type of RAID array you formatted then to.  If it is RAID 1 then it is easy compared to the other RAID types and you have two exact copies of the data.

Read the 'Data recovery' sticky in this forum and ask if you have any problems. 

[RobertSteed]

Thanks for that. I don't know which RAID type it is, but it's one where it is one volume over both HDDs, no redundancy.

[ivan]

That sounds like RAID 0 which requires specialist software to do the recovery and a lot of space on your computer hard disk or a USB disk with enough capacity to hold all your data.

Then you also need a USB/SATA adapter with an external power supply to allow mounting of the disks.

I would advise you to first download the Recovery Manual PDF from the R-Studio site and read through it to get some idea of what you need to do to recover your data (you could end up wishing that you had made a full backup).

Other than that - good luck. 

Edit:  The reason I mentioned R-Studio is only because they have clear and freely available manuals for those with Windows or Linux operating systems - reading and understand the manual is essential to successful recovery of data.
 

[RobertSteed]

Thanks. Is it not possible to mount the drives in a PC and configure them as a RAID array, possibly under Linux? Or could I buy a new NAS and drop the HDDs in and configure them as RAID?

[ivan]

Simple answer no.  It would be yes IF, and only IF, they had been setup as a RAID 1 array.

A RAID 1 array has two disks that are exactly the same.  You can therefore take one disk and, providing you can read the Ext2/3 format, have access to all the data.  Its function is to allow you to have access to your data should a disk fail.

Any of the other RAID arrays (RAID 1, JBOD, RAID 5) have the data held id 'stripes' spread over the disks.  This means that one part of a large file could be on disk 1 with the remainder of the file on disk 2.  The array keeps track of where the information by storing 'parity' information on the disks.  To recover the data from these arrays requires software to read the parity information and put the data back together in a form that can be used.

Since most RAID arrays are 'software raid' (the exceptions to this are the hardware RAID arrays used in servers and storage arrays and cost several orders of magnitude greater than software raid) the exact setup varies depending on the software implementation and device firmware.  Hence it is very unlikely that just transferring the disks into another NAS box is going to recover the data.  Again there is an exception, if the replacement box is of the same series and has the same firmware and the disks are placed in the same order there is then about a 90% chance of success..

[RobertSteed]

The RAID 0 did work straight away in the replacement DNS-320, to my amazement. I'm pretty sure the replacement NAS didn't have the same firmware (it had an older version). I can't be sure the discs were in the right order, must have been luck.

Thanks for all your help everyone.

[ivan]

I am very pleased that it worked for you and you access to all your data.