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Mac OSX: LaCie 4TB drive unreadable

Posted on 2011-03-01
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Last Modified: 2012-05-11
Hey,
I have a LaCie 4TB Quadra unit that was connected to my Mac. All the sudden I can no longer open it and it is unreadable. It's a 4 1TB drives in a RAID config (setting 0) to show as one large 4TB drive. The switch on the back makes the RAID config work properly.

Questions:
If I troubleshoot this what happens if I switch the RAID button from settings 0 to settings 1,2,3,4,5,6,7? will it clear the drives? will it just show up differently on the computer until I reformat it, then its gone? Or will it change the configuration for the computer only temporarily, then change back without harm as long as I don't format it again? confusing, i know. hard to explain!

other than this, I loaded it onto a different machine and decided to do the general mac testing PAB-HD.tiff
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Question by:Justin_Edmands
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by:LectricX
LectricX earned 250 total points
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Do not change the RAID mode!

Taken from the LaCie 4TB Quadra manual found at:
http://www.lacie.com/download/manual/4big_Quadra_en.pdf

"Changing the RAID mode destroys data stored on the LaCie 4big. If you have saved data on the drives, back up data before following these steps."

If it is currently set to mode "0" here's some knowledge you will need to know, but may not like:

1:  The 4big Quadra is pre-configured in RAID 0.
2:  If one physical disk in the array fails, the data of all disks becomes inaccessible because parts of the data have been written to all disks.

If you are having trouble getting to your data, you might have a failed disk.  Sorry.
You may want to open the Manual and go to page 32 for the TROUBLESHOOTING tips.

Best of luck.
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dlethe earned 250 total points
ID: 35011759
Well, I have not been inside of this device, but the Lacie 2Big is not much more than a linux computer doing software based RAID.  I expect the 4Big is the same.  That being said, if you are talented with LINUX, you should be able to accomplish quite a lot and perhaps recover the vast majority of the data.   The 2Big uses XFS file system, which means a custom LINUX kernel.

This is not the sort of thing that anybody can walk you through.  The type of person that says, "Wow, LINUX md driver with XFS file sytem & software RAID, that is all I needed to know ..", pretty much has all he/she needs to get the data back.  If this isn't enough, then you need to either contact LaCie, and be prepared for $1000+, or find some expert/consultant/ experienced sysadmin you can contract.

Personally, you would be much better off if you just bought yourself an add-on card and used native OS X software RAID, or a supported hardware RAID controller in the future.  Kind of silly to add all that latency for a software-RAID which has near zero overhead and all the conversion that has to go with it    You probably also know if you lose a disk in RAID0, then you lose 100% of the data.  

No matter what, you can do a do-it-yourself thing by booting a PC to LINUX, attaching those disks and running hardware diagnostics.  If the drives are all OK then either the metadata got blown, or the O/S destroyed on the appliance .. or you lost a $100 controller card that you can probably get cheaper by buying a replacement unit diskless.
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