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Our RAID controller failed; it doesn't show up with a boot menu anymore, and the BIOS finds no disks. When we get a new controller, can we recreate the RAID set without losing data? IIUC, the controller has the configuration in RAM, not on disk (and yes, we have the extra batteries for the RAID controller installed - but that may not help as the controller is unresponsive).

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3 Answers

up vote 1 down vote accepted

Generally RAID information is stored on the disc, but get the exact same raid controller. The controller should just read that information from the disc and you should be good to go. I don't have experience with this exact controller, but that is the case with the Dell Perc controllers.

See this answer to: How to replace a SCSI RAID controller without loss of data? on Adaptec's site:

Each disk attached to an Adaptec RAID or HostRAID controller which has been initialized for use in an array includes a special data structure referred to as metadata. This data structure defines the configuration of the disks, partitions, and arrays created by the controller. The metadata allows you to swap an entire array from one controller to another, or swap the controller itself, without reconfiguring the partitions or arrays.

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If you read that link, might not have to get the same controller... –  Kyle Brandt Aug 10 '09 at 23:09
    
Thanks, this sounds very promising. –  Martin v. Löwis Aug 11 '09 at 3:48
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Adaptec controllers store the raid layout info at the start of each disk.

So get the exact same model and ensure the same firmware version is used too!

You should be able to swap controllers and on first boot up select the option to recover the array/load the existing array.

If that is hosed too due to the previous controller going tits up, you can always recover from your backups right...?

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Yes, we do have a backup. It is a few hours old, so we would rather prefer to continue using the same disks. –  Martin v. Löwis Aug 11 '09 at 3:44
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How brave are you? And It Depends TM

I've had RAID-0 and RAID-1 saved by knowing the exact stripe size and re-configuring the replacement controller with identical settings. That said, RAID-5 is a much much much much more complex situation than RAID-0, so your milage might vary.

That said, it's a very scary thing to do. If you have enough spare space, I high recommend Zero Assumption Recovery. I've used to to recover RAID-0, RAID-1 and RAID-5 disk layouts from within Windows. If you can get a copy of the data the world won't end if it all gets lost...

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