4 Replies Latest reply on Jun 17, 2009 8:11 PM by nicolas.qiu

    Question about Raid metadata on disk


      When PC power on, bios will write raid info to the last 2 sectors on disk

      I want to analyse the raid metadata on disk in my OS,

      I've looked all over Intel for an answer to my questions, but haven't found any. Any help is appreciated.

      Anyone who can send me a copy, thx very much.

      Email: qiuting200@gmail.com

        • 1. Re: Question about Raid metadata on disk

          Ehm, the controller builds a volume that translates to a HDD in the OS. The metadata (if any) is writtin on the DISK, not the volume, which is not available to the OS, since it's "beyond" the HDD limit. To read that You'll need to have a chat with the controller.


          I'm not even sure the data is available AT ALL. I don't know how it's done in real life but if I would have designed the thing it wouldn't. In stead, the driver would chat with the controller via normal expansion card protocols and it would report whatever it wants. Making data available via instructions would mean that an error in an addressing API could overwrite it and as a result an OS crash could break the array. That would be bad, as bad as a mistake in a RAID controller gets. So I'd make it unavailable. Especially since I pretty much know the darned kids are going to OC make the memory and OS fuzzy.

          • 2. Re: Question about Raid metadata on disk

            I just need the metadata which bios write on disk,

            I want to analyse the data, but I don't have the data format specification,so the only way is to read linux code, some field I only depend on guessing.

            My motherboard is using Intel soft raid, so I think it can find in intel,but I can't find it.

            Thank you very much for your reply.

            • 3. Re: Question about Raid metadata on disk

              Ooooh, a software RAID.


              Then you should be able to read if you access the drives directly. I still think you can't do this via normal compiler, you neet at least a kernel driver to access hardware, but once you read the actual disk not the virtual disk the driver creates you should be able to read the data.


              As for the contents, you still need to read the Linux source to figure it out.


              OTOH, you should be able to get the info you need accessing the driver and asking. You need to read the L source any way you put it. As for specifics, such as source code, I think you are out of luck. I've seen much simpler questions go unanswered (like mine) so you either take it to a developer forum (this is support) or you start reading Unix code. Or ask someone to do it.


              Are there no tools that do that on Windows? Look around, some might be free and willing to share results.

              • 4. Re: Question about Raid metadata on disk

                Thank you for your help,yes, a software raid.

                I write it in my own system, it's not linux.

                I just finish it, but I want to know the details about the metadata.

                I think it's complicated here, can you give me a link which forum I can get the answer.

                Thank you