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Adaptec RAID reconstruction

Posted on 2008-10-02
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Last Modified: 2013-11-14
Hi,
I have a Adaptec 2610sa configured with 750gb x4 in RAID 5.  It has to have 2 logical devices (2tb limit) so it has dev1 (2tb) and dev2(50gb).  (these are then in Linux LVM - gives me 2.1tb as one volume)
One drive failed ("drive 1), no problem so far, card automagically tried to rebuild with defect drive in place.  It successfully rebuilt dev2, however on rebuild dev1, the computer switched off (i think i have a power supply issue).
On restart - card reports Dev1 as "FAILED" (reports Drive 0+1 as failed), and dev2 as "DEGRADED". (reports drive 1 as failed).
So I believe that the data is all intact, just inaccessible.
I've used Raid Recontructor (Runtime) with great success with a previous adaptec raid failure, however that RAID had only one logical device (not 2)

QUESTION:
Has anyone any experience with extracting logical devices with raid recontructor?

THe optimal solution would be to have RR dump 2 image files - one 2tb, the other 50gb. I can then use losetup and vgscan to rebuild by LVM.

or will I be presented with one file, containing both devices.
IIF SO,
What methods are available to extract the logical devices from this file?

Theoretically I could make an image of dev2 - its classed as degraded and therefore still accessible - but i don't really want to use it to on the current system - i'm not sure of its stability.
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Question by:djscuzzy
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by:rindi
ID: 22632259
The Raid reconstructor shouldn't really worry about how you have partitioned your array. The It will just try to restore the array itself. I'd just try using it, as you don't really loose anything if you try.

But first you should resolve your issue why the array failed in the first place. You mention:

"card automagically tried to rebuild with defect drive in place".

What does that mean? you left the bad disk inside? Why? If there is a bad disk, you should replace it and only do the rebuild after that.

On the other hand, if you think the "Bad Disk" is actually good, then a reason for it's failure is often a power issue, like the Power supply of the the PC isn't strong enough to supply all disks, or sometimes the power cables to the disks aren't good. If you have such an issue you must first fix this, as this is a dangerous situation and any further failure can cause serious data loss. A degraded raid 5 array is very easily lost if you have a further power issue while it hasn't rebuilt itself yet. Make sure you really have a good power supply before you carry on.
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by:djscuzzy
ID: 22640525
When I mean, automagically, i mean that the card must have detected an abnormailty, thus decided to rebuild the raid.  It does this without intervention, therefore I didn't even have the chance to remove the drive.

So, I tried RAID Reconstructor.  It seemed to find a configuration, and produced a virutal image. Although their other data recovery tools could not find the linux filesystem.
My step would be this: dump the RAID to an image file.  This would provide me with a 2.05tb file. This file should contain /dev/sdb and /dev/sdc of my linux LVM in one file.
If I had a separate file for each (/dev/sdb and /dev/sdc) I have a fair idea how to fair idea of how to rebuild the LVM.  

But in one file? I've no idea.
Further question: how is an ext3 fs laid out in an LVM ? could I search for text that know should be there? (thus confirming that the RR output was correct)
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rindi earned 500 total points
ID: 22646281
I think first you have to, like I mentioned, resolve the reason for the array failing in the first place, so it won't happen again (PSU, cables etc).

As LVM is just the container of your partitions, like a single HD, it shouldn't really matter if you had used EXT3 or whatever as the filesystem within that. So after you have the virtual image you should be able to scan it using Linux tools to recover the data (of course not runtime's getdataback as that's just for fat and ntfs).
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