NASLite Network Attached Storage
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PostPosted: Sun May 20, 2012 6:12 am 

Joined: Wed Oct 05, 2011 12:00 am
Posts: 61
I run an 8 disc system - 4 for data storage and I mirror those 4 using NASLite admin.

Yesterday, something happened to disc 3 and all the data was lost, then NASLite mirrored the disc to 4 resulting in the back up mirror also being erased.

It's awesome losing all data.

Tell me, can NASLite be built with an algorithm that detects drastic changes in data, or checks the drive for any problems before enabling a mirror backup? Kind of stupid losing all that data for no reason.

The only way around this for me to get past this problem is to do a third manual data mirror every few weeks. Which is kind of pointless isn't it? I mean, why have a NAS in the first place?

Cheers, Mark.

*Edit - Could this be moved to the NASLite M2 forum? I posted here accidentally from a google search on NASLite. Otherwise I will create another post like this in about a week.

PostPosted: Sun May 20, 2012 9:52 am 

Joined: Sun May 27, 2007 5:38 pm
Posts: 517
Location: gods own country
but nothing may be lost - there are plenty of programs to bring the files back - the original disk has gone if its faulty - but even that may not be the case - if the circuit board has blown then the data is still on the disks - try a circuit board change in that case

the stuff on the mirror may be over written but that does not mean it cannot be restored - in windows thats certainly possible - in linux there are sure to be similar programs - have a search

PostPosted: Sun May 20, 2012 10:44 am 

Joined: Sun Apr 02, 2006 9:05 pm
Posts: 1688
Location: Up State NY in the USA!!!!
That is a bummer to say the least. That is the problem though with a mirror rather than a proper full/incremental backup.

As far as the data still being on the first disk, baring a head crash that damaged the disk, it is still there. Problem is that the cost of recovery is usually rather steep. On older disks you could use a board from another exact same drive and get the data off. Not so sure about now days with the new drives as there is allot going on in regards to tuning the DSP on board to the HDA. It may or may not work.

There are in fact a number of solutions to recover lost data on an EXT3 partition that has been overwritten. A quick Google search should yield a list of them.

For future use, others seem to have good luck with Acronis and I know of a number of people that use it to back up.


PostPosted: Wed May 23, 2012 12:40 pm 
Site Admin

Joined: Tue Jul 13, 2004 4:11 pm
Posts: 1771
Location: Server Elements
The disk simply dropping out without chocking the mirror handler is strange.

When NASLite-2 boots, all storage devices get detected rendered and recorded to a device index which is used during system operation. The mirror event runs a number of checks that must pass prior to the event actually happening.

Especially in your case, where the mirror is local, the mirror will not execute unless the source drive, addressed by device node, passes SMART. If it fails, the mirror dies with error. If the drive is off-line then it's device node will produce a SMART failure since there is no firmware to respond to the query. In turn, the blank source folder can only happen if the drive has failed and was taken off-line by the driver, leaving an empty mount-point folder. In other words, if the device node passes SMART, the drive should be online.

So, how can a drive drop offline while still passing SMART?!? - This is definitely strange.

In order for this to happen, the drive should fail temporarily, get dropped from the chain leaving an empty mount point, come back online (this will definitely produce errors in the syslog) and not get remounted. I've never seen that occur, but who knows...

I'm shooting in the dark here but are you using any IDE to SATA or SATA to IDE converters, any unique adapters, controllers, anything strange? What is the exact setup you have?

PostPosted: Sun Aug 26, 2012 1:20 pm 

Joined: Sun Aug 26, 2012 1:13 pm
Posts: 3
Hi Tony,

Is there any documentation that discusses the topic of mirroring in greater detail? Something similar to what you discussed here that outlines the various checks that need to occur for mirroring to take place? I checked the user manual and did not see this level of detail.


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