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PostPosted: Tue Oct 23, 2012 9:22 pm 
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The story: 2big network with a pair of 0.75 Tb discs, raid 1 mode, OK. I expect increase in data quantity and purchase a pair of original LaCie 1 TB discs, with their bay.
Run down the box, insert NEW pair of discs and re-boot, reconfigure a new set of shares etc. OK.

Data set 1 on PAIR 1 is different than data 2 set on PAIR 2.

Use PAIR 2 for a while. Now there is a need to have access of some old data stored on PAIR1. Log off, power off, swap the pairs, re-boot, apparently OK.

There is a little however : the data of PAIR1 is apparently gone. So are the shares.

Swap back to PAIR2, same scenario, data and share are apparently gone. I don't believe that data is gone, but the box is apparently not capable to deal with two pairs of discs.
What is the rationale for that behavior ? Any advice ?

Kind regards, Philippe


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PostPosted: Wed Oct 24, 2012 9:31 am 
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The 2Big2 has a small eeprom, which contains the UUID of the raidarray. A new (pair of) disks has a special marker. When this marker is detected on boot, a new raidarray is created, the UUID is written in eeprom, and the marker is removed.

I *think* the purpose of this eeprom is to identify the 'real' disk, when from a raid1 array one disk died, and is exchanged by a used disk of another Lacie box. (It would be *very* frustrating when the box would synchronize the wrong way!)

The bootscript I studied will just refuse to boot when no one of the disks contain the right UUID, and drop a shell (on the serial port). However, that is on the 2Big2 (and could be changed in firmware updates).

Seeing your experience it seems the 2Big also has that eeprom, but behaves different when booted with the 'wrong disks'. The 2Big2 will just refuse to boot, and everything is fine when you restore the 'right disks'.
I can be wrong, but I'm afraid it just created new raidarrays when the UUID didn't fit, and wrote the UUID of the new array on PAIR1 in eeprom, so that restoring PAIR2 didn't work either. (And also created new arrays)
In that case your data isn't actually wiped (that would take several hours) but a new filesystem is written over it.

My advice? Depends on the presence and recentness of a backup. If you don't have a backup, switch off the box immediately, and prepare a Linux PC to analyze the disks and to recover your data (any PC booted from a Linux Live CD or -USB stick will do), or bring the disks to a professional data recovery company. (That will cost several hundreds, may thousands of euro's)

Are the disks in raid0 or raid1?


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PostPosted: Wed Oct 24, 2012 4:22 pm 
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Good afternoon, and thank you for the reply.

Both pairs of discs have been configured and used as Raid 1.
Currently Pair 2 (1 tB) is active and works OK. I'm interested to recover some of the content of Pair 1 (BU of Pair 2 being available !!! :!: )
The "frustration" with this: NOTHING in the LaCie manual gives a hint about such a potential problem. The techs at Lacie were indeed nice but could not help.

Your advice: " ... prepare a Linux PC to analyze the disks ..." can you please point me to some readings ? I'm sure all of that has already been documented, and I don't want to waste your precious time.
Will the "apple" flavor of Linux do the job ?

have a nice evening, Philippe


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PostPosted: Wed Oct 24, 2012 6:18 pm 
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Filou wrote:
Currently Pair 2 (1 tB) is active and works OK.
Great. That that increases the likelihood that Pair 1 is also ok, and the box just refuses to mount it.
Quote:
Your advice: " ... prepare a Linux PC to analyze the disks ..." can you please point me to some readings ?
Live CD, Low level file recovery.

With some luck you don't need to recover anything, just mount the data partition. Connect one disk to your Linux box (by sata, e-sata, or an usb to sata converter).Find the device node of the data partition; open a terminal, and type
Code:
cat /proc/partitions
The size is given in kB, you are searching for an almost 750GB partition. I'll assume it's sdb2. Mount it:
Code:
mkdir /tmp/mountpoint
sudo mount -t xfs -o ro /dev/sdb2 /tmp/mountpoint
If this works, you can use the GUI to access your files in /tmp/mountpoint. The partition is mounted read only, in case the filesystem was overwritten. In that case you should not write anything to the disk, to prevent further data damage.

Filou wrote:
Will the "apple" flavor of Linux do the job ?
What do you mean? Linux on an Apple? Afaik an Ubuntu Live CD will also boot on an (Intel) Apple. Or is there some distro called apple? Actually any Linux which supports the xfs file system (which is almost any Linux distro younger than, say, 4 years) can mount the disk that way. Even the 2Big can, if you have a shell. When the filesystem is overwritten it becomes a little more complex. Theoretically still each Linux system works, but not for all flavors all recovery tools are available. It is possible to compile PhotoRec for the 2Big, but that's a different story.


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PostPosted: Wed Oct 24, 2012 7:33 pm 
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Joined: Tue Oct 23, 2012 8:59 pm
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Thank you very much !

Filou wrote:
Will the "apple" flavor of Linux do the job ?


Mijzelf wrote:
What do you mean? Linux on an Apple ?


Sorry about that, I did not want to offend anyone. I seem to remember that Unix and OS X share similarities, and that Linux is not far along a parallel track. So I wonder if it is worth trying to mount one disc of pair 1 using a OS X box from the console.

I wish you a pleasant evening, Philippe


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PostPosted: Wed Oct 24, 2012 7:57 pm 
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Filou wrote:
So I wonder if it is worth trying to mount one disc of pair 1 using a OS X box from the console.
Maybe.


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PostPosted: Wed Oct 24, 2012 8:56 pm 
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Hmmm, good point: the main issue is probably that OS X does not deal with XFS file system. And hacking this is not my goal. It seems easier to boot a Linux box first thing tomorrow, after coffee !
Again thank you for your help. :D


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PostPosted: Fri Dec 21, 2012 7:08 pm 
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Joined: Tue Oct 23, 2012 8:59 pm
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So, its been a while, was also busy with other issues.

One disc of the array 1 pair connected via USB to a Linux live box.
The catalog of the partitions lists the 750 GB disc as several "pieces" sbc, sbc1,2, ...10 etc.
A mountpoint has been created in /tmp
Source will be sbc or sbc1 whereas target is tmp/mountpoint.
The sudo mount command requires, among other things, a -t FS.
Several file system (FS) types have been invoked: EXT2, EXT3, XFS, etc, none seem to match.
The error messages sent back by "mount" hint towards "unrecognized FS" as if all attempts to read the disc failed.

Are there any other suggestions ?
Wish you all a nice Maya Calender Cycle Party followed by a Merrry Christmas.


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PostPosted: Sun Dec 23, 2012 12:18 pm 
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A few thoughts.
Quote:
Source will be sbc or sbc1
sdc is the whole disk, while sdc1..10 are partitions. So you should not mount sdc, but one of the partitions. How confident are you about sdc1? All Lacie's I have seen have their data on sdc2, while sdc1 is an extended partition containing sdc5...10, which contains the OS, which is of less interest for you. But of course on an old Lacie this could be different. If 'cat /proc/partitions' shows sdc1 as the biggest partition, it certainly is the data partition.
Quote:
Several file system (FS) types have been invoked: EXT2, EXT3, XFS, etc, none seem to match.
You should use the lowercase names, ext2, ext3, xfs, etc.


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