I have a client who called me because her Windows 7 machine was not booting. I booted with my Ubuntu live disk and ran fdisk to get a list ing of her hard drives and partitioning structure.

This is what fdisk outputs:



First of all, why do the hard drives skip letters? It jumps from sda to sdf with no devices in between. As far as I could tell there was nothing else connected to the system except the 3 internal hard drives.

Also, what are the /dev/mapper devices listed at the bottom? It looks like they are copies of partitions on /dev/sda. I don't think RAID is configured but I could be wrong...

What is going on?

I appreciate all feedback.

If the machine has attached card readers, etc., with no media inserted, those will be given sdX names but will be ignored by fdisk since there is no media. For example, my printer also functions as a card reader (CF, SD, XD, MS cards), and thus appears as /dev/sdd, but is ignored by fdisk (I never use it -- only works with photo cards).

The "isw" prefix indicates Intel Storage Matrix RAID, which is supported in both MS Windows and Linux.

Thanks for your feedback. So are you saying that RAID is setup on this machine? Also, /dev/sda reports only 500 gigs of space but contains a 1TB partion.

Would this suggest that the two 500 gig drives on the machine have been combined?

It certainly appears that RAID is set up on the system and that Linux is confused by it. I have no familiarity with Intel RAID beyond a quick Google search, but it looks to me as though Linux is applying the partitioning of the composite RAID device to the individual disks.

Are there just two physical disks on the machine? I notice that the partitions of the 500GB /dev/sdg also add up to more than 1TB. EDIT: They don't.

I think you need to provide more information on the actual hardware layout in the system. You said in the OP that there are three internal drives, then you said in post #2 that there are two 500 GB drives. What about the third? Are the drives actually 500 GB or are you just saying that because that's what you're seeing in fdisk? What's with all of the Linux partitions on sdg? Does this person actually have a Linux OS installed on the machine or does this have to do with your Live system that you're booting up, or some other drive you have attached?

Open up the case, count the physical drives and get their sizes, and report back what you think is on each one.

I opened the case to gain some clarity and there are 2 identical drives (500G) and a single Terabyte drive.

/dev/sda reports 500 Gigs yet contains a 1TB partition /dev/sda3.

What is the best way to approach this situation if I wanted to dual boot Windows and Linux but save the data on the partitions?

Write down the serial numbers on the three physical drives, and then use "smartctl -a" to pair them up with the drive letters assigned by your live system.

My interpretation is the following:
sda and sdf are the 500 GB drives, sdg is the 1 TB drive, and the two 500 GB are in a RAID 0 (or similar) using the Intel chipset. Since they're in a RAID 0, fdisk is reporting the partition information for the full array on sda, and no partition information on sdf since it just contains an "extension" of sda.

If this is the case, don't try to mount sda or sdf individually, instead mount the isw array partitions and back up the data onto an external disk before trying to do any OS installation.

Thanks. Now that you mention the raid 0 it does appear that SDA and sdf are in that type of configuration. But if that is the case, how is the terabyte drive /Dev/sdg showing more than a terabyte in all of the partitions? Could this drive be part of the array somehow?

I will note down those serial numbers when I get a chance.

It's not. I made a mistake there. Partitions 5, 6, and 7 are logical partitions that exist within the extended partition sdg2. Everything looks normal on that drive.

Well what's it doing when it doesn't boot? Can it get to BIOS at all? What is it saying about the system disk? After all, the person is trying to boot Windows 7. Seems to me that a recover or repair process for Windows 7 would be more applicable. Sure you have information about the partition table because you booted via Live Linux, but this does not address the actual problem your client is facing. I would seek out information related to how to recover and repair Windows 7 boot.