Migrating LSI Megaraid to new motherboard

If I understand you correctly, you had a RAID 10 setup on your old LGA775 motherboard on the embedded software SATA controller.

Then you bought a MegaRAID and a new motherboard.

You might be able to recover the RAID set if you can correctly pair the "1" sets of the RAID 10 array to the LSI card. When you boot the new setup, you should receive a "Foreign configuration" message. If you select "Import Foreign Configuration" the LSI card will read the metadata from the old HDDs that tell it what kind of array they were in and try to import it in to a new array (it will build the array automagically). BUT, it's very risky. If you fail to place the drives in the proper order, the array is toast. Permanently.

You may actually have better luck putting the four drives in an array on the new motherboard's SATA controller (assuming it supports RAID 10). You must still have the drives in the correct order.

You are really between a rock and a hard place.

Another thing to consider, you should be able to break the RAID 10 into a RAID 0 by simply not installing one drive of each RAID 1 set (it's a mirror). In this case, you would not select "import foreign config" but rather simply create a RAID 0 set and then attach a single drive from each RAID 1 pair and do not initialize. If it recognizes it, great, if it doesn't, not so great.

As for remembering whether it was RAID 10 or RAID 01, just look at the motherboard specs. I have never seen a motherboard natively support 0+1 (RAID 01). RAID 01 is generally implemented by creating 2 RAID 1 arrays and then striping them (RAID 0) via the OS.

In any case, putting the drives in the wrong order wil not only not work, it will most likely destroy the data that is on them (the import will be attempted and the build will fail) and then you'll be SOL with zero chance of any recovery.

There's a lesson to be learned here (actually several).
1. Always backup externally.
2. Don't use the motherboard's built-in SATA RAID controller. (for reasons that should be obvious in hindsight)
3. The vast majority of people have no business using RAID. At all.
4. And most importantly, see #1.

Thank you!

That helps.

Will clonezilla clone 1 drive out of a RAID set? Then I can experiment without toasting the array.

Yea, that's the funny thing, I DID backup externally. However, the later backup corrupted the first, and I had no way to know until I tried to restore the backup.

At work, we do that stuff all the time (restore backups), but not so often at home  

But - point taken.

I also had a backup of important files I'd copied manually, so I haven't lost everything, just some older stuff I really would like to get back.

I didn't buy a separate LSI card, this is just the embedded motherboard controller.

Good to know about 'import foreign configuration'. I have an extra drive or two of the same type of RAID, I'll see if I can do clonezilla FIRST from the raw drive(s) on the set.

== John ==

Let us know how that turns out.

The RAID controller will have the configuration stored in NVRAM. Normally a RAID controller writes signatures to the disk and should be able to detect the configuration of the RAID Array. As long as you do not save the configuration to either NVRAM or to disk, you should be able to power off and try several configurations if for some reason you need to. If you get the array online, the first thing I would do is image the volume as a backup.

Thanks!

The RAID signatures on disk, are those industry standard? I assume they go in a separate configuration partition.

Ideally, you could pull the physical partitions off as VHD's and connect them in software RAID, but that's a really long shot. I assume these configuration parameters are pretty controller specific (not even brand).

Hard to get firm data on this stuff.

I hope to fiddle with things this weekend, will let everyone know what happened. I imagine other people go through this from time to time.

== John ==

Well the signature I believe is normally written as by the controller at a lower level than the partition level. You won't see it as a separate partition. This is pretty standard on enterprise controllers (SCSI/SAS) from LSI. I have not worked with their MegaRAID controllers before, but I have a lot of experience with LSI's enterprise SAS controllers. The signatures will definitely be controller specific. Just make sure you do not write anything out until it is working. In a worst case scenario, if you can't get it to work, connect the drives via a non_RAID controller, get a lot of external storage and you can reconstruct the stripe set using a number of software utilities out there. R-Studio is probably may favorite, its affordable but not free. RAID 10 with 4 drives will be easy to rebuild. I've done 12 disk RAID 10s before and 6+ spindle RAID5s successfully.