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Some time ago, I attempted to upgrade a RAID 1 array to a RAID 10 array by adding two more disks to the original two that lived in an IBM xSeries 346. In the RAID card's bios, I told it to grow the array onto the new disks, and for whatever brain-glitch reason I checked the "striped" box. This just striped the old RAID 1 array across the new disks without upgrading it to RAID 10. The RAID card reports that the RAID level is "1E".

Naturally, I was quite dismayed to find that the array was no bigger than when I started.

Is there any way I can fix this? Can I pull the new drives (with the intention of formatting them and starting the upgrade again) without destroying the array?

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So your RAID 1 is now 4 disks? 2 main and 2 mirrors, or 1 main and 3 mirrors? – JohnThePro Apr 23 '12 at 17:46
Yes, it's 4 disks, but I wouldn't call it 1 main and 3 mirrors. It appears to be the original RAID 1 mirror array striped across 4 disks like a RAID 5 array, or something. But I'm also a little fuzzy on this point. – Ernie Apr 23 '12 at 17:52
Huh, that's a bit strange. When you look at the RAID controller, what configuration does it say it is running in? It's a bit of a situation you have yourself in... but push comes to shove, the original two drives SHOULD have the entire array's data on it. If needed, you could remove the two new drives from the array without data loss, and then re-attach them. AS LONG AS YOUR OPERATION DIDNT CHANGE ANYTHING ON THE FIRST TWO DRIVES. – JohnThePro Apr 23 '12 at 17:54
What RAID card do you have? Or is it merely the integrated RAID support within the 346? – Wesley Apr 23 '12 at 17:57
@WesleyDavid: Yes, it's the Built-in hardware raid on the 346; Specifically a ServeRAID 7k controller. – Ernie Apr 23 '12 at 19:07

The recommended way from IBM is:
1 - revert to RAID 1 with 2 disks. This will require a full synchronisation (because RAID 1E is a stripped system, not RAID 1)
2 - upgrade to RAID 10

note: with 4 disks in RAID 1E you should have twice the capacity because RAID 1E is designed to give 50% of total disk space (if same size). So check if you really are in RAID 1E before doing anything

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Hmm, that's strange. IBM's ipssend program says that the controller really is in RAID 1E, and these drives are definitely all the same size. All drives are likewise online according to ipssend. – Ernie Apr 24 '12 at 15:11
I don't suppose there's any documentation on how to do this, is there? – Ernie Apr 24 '12 at 20:25
There:… but this is not better than just using the management tools, which are relatively easy to understand. – Gregory MOUSSAT Apr 25 '12 at 0:00

I found the problem (mind you, this was done in a highly non-optimal way). This will be relevant to anyone who tries to follow Gregory's advice.

  1. You can't revert to RAID 1 with two disks under RAID 1E. RAID 1E, just like RAID 5, can only have one defunct drive at a time. Doing anything to fix this problem will result in re-configuring the RAID. You will lose all your data.

  2. You can't use RAID 10 on the ServeRAID 7k, which was part of the problem way back when I installed the new drives. As far as I can tell, the only way to grow the virtual disk is by creating a new partition in the ServeRAID software with the new space. It will not add space to the existing partition, despite how the documentation suggests otherwise.

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