LSI MegaRaid - Image Drive from Failed RAID

Question

I had a power failure and my LSI MegaRaid 3 disk SAS RAID 0 failed. My attempts to recover the RAID have also failed.

I plan to rebuild the array and go with RAID 5 and add another SAS disk.

However, before I wipe the drives I would like to image each of them separately.

I tried to boot up using a Linux live boot CD. I can boot up but I can't see my drives. I tried just one drive plugged in and booting but the drive can't be seen so I can't call the imaging command.

I'm assuming since the MegaRaid SAS controller says that the virtual drive is bad, then it will never mount.

I tried to find a SAS to USB cable online so I could just plug in each drive and image them but I can't find such a product.

I thought maybe I could use the MegaRaid controller with one drive plugged in and set it as a new Raid 0 so I could get it to mount. However, it seems to want to call the initialize command and want to wipe the drive. Losing the Raid tables for the original Raid wouldn't be a problem, but I don't want the data to be erased.

Any suggestions on how I could image each drive?

------ UPDATE --------

@ ewwhite

Correct there was no redundancy, it was a bad setup. There was a power outage and when then the RAID failed to boot. SAS controller status said its "Offline", one drive says "Bad" and the other two are "Good". I tried to "Make Good" and "Put Online" the Bad drive and it turns green and the virtual drive says Good and Online. However, whenever I try to boot again I get the same error, RAID starts to beep and the drive says "Bad". Not sure what other options I have to resolve it. I assume the RAID table / controller data was compromised.

I would still like to image the drives individually. There are some programs that can attempt to recover the data by passing the drive images, setting the stripe size and then analyzing the data. However I have no idea how people are getting the individual drive images.

I understand I can't mount the array of disks but I was hoping I could mount them one at a time. Perhaps connect just one and set it as a RAID 0, but I can't figure out how to do this without erasing the contents of the drive. If I lose the RAID table data then that would be ok.

@ kasperd

JBOD or some kind of "pass through" option would be exactly what I need. Disabling the RAID and just mounting a single drive.

I looked through my controller options but did not see any option like that. I have emailed the manufacturer asking about this but it doesn't look like it supports it so far.

Please let me know if you have any other thoughts.

Answer 1

Are you saying that you had three SAS disks in a RAID 0 arrangement? That means that there was no redundancy.

Do you what specifically about the power failure impacted your environment?

Was there just a power outage? A power surge? Electrical storm? Lightning?

I'm not certain that a power outage would result in an array failure... However a failed disk COULD result in array failure.

When you look at the SAS controller's status, what does it say? Please post the details in your question. Regardless, you did have a RAID 0 configuration, so a failed disk means your data is likely unrecoverable. Remember, RAID 0 strips the data across the member disks. So recovery would be challenging.

Do you want to image the disks knowing this information?

As for mounting the disks, this may not be possible without specialized tools. Those drives have array metadata, and at this point, the array has failed. Again, details will help, but you wouldn't be able to just mount one of the disks.

Also, you're right... USB->SAS adapters do not exist.

Answer 2

RAID0 is not the proper configuration for mirroring individual drives. What you need is a SAS controller without RAID functionality. On some (most?) controllers you can disable the RAID functionality by choosing to use JBOD. If your controller has such a setting, I would expect it to be useful for imaging your disks.

If your current controller cannot do it, you may need a new one. Obviously it need to be SAS on the drive side, on the host side it could be anything your host supports. I'd be surprised if there did not exist a SAS enclosure with a USB connector. But it might be a lot easier to find a SAS controller using PCI or similar.