Why are two different hard drives listed as one disk in Disk Management?

I feel like there's something going wrong with my hard drives on my computer... Yesterday two I use for storage (M: and H:) stopped working altogether. Today they came back and seem fine, but now I just noticed that they're listed as DISK 1 in Disk Management.

What's going on? Why are two different physical drives, which two different drive letters, listed under "DISK 1", and is this something I need to change?

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Note: I'm not talking about my RAID array!

Django Reinhardt

Posted 2014-04-24T15:25:48.783

Reputation: 4 183

Your screenshot gave out some clues. Both disk are Dynamic. And Documents (G:) Layout is Mirror. You have somehow set both disk to mirror each other (RAID1?). So yes it looks like you lose 50% capacity (lose 1 HDD capacity), but you have a bit of extra redundancy (if either Disk2, or Disk3 fails, you still have a perfect copy). – Darius – 2014-04-24T15:55:37.697

@Darius I've made my question clearer. I'm not interested in the RAID array. – Django Reinhardt – 2014-04-24T17:50:53.030

Sorry I guess I was a bit confused. Each "Disk" are often referring to a physical disk, so Disk1 is basically a 3TB Physical Disk, which have been separated into 2 partitions (2TB and 1TB respectively). M and H are not in a separate physical disk. You can try to confirm this by booting to your BIOS to see what does the BIOS see, and confirm if there are actually a physical 3TB HDD. Note: If you have a physical RAID card (not RAID inside windows), they can make multiple HDD visible as a single HDD under windows. – Darius – 2014-04-24T18:22:22.533

2@Darius facepalm I completely forgot something: I used to have four harddrives. I switched two out for one, and created a partition on the old one that mirrored one of the old harddrives. I was thinking that that the new HD was M: and I still had the old one (H:). Doh! – Django Reinhardt – 2014-04-24T18:26:01.000

Good to know you solved it. For sake of completeness can you summarise your comment ^ as an answer and accept it please? – RJFalconer – 2014-05-05T13:45:38.390

Answers

This is a rather silly. I forgotten I'd removed a harddrive and replaced it, exactly as it was, as a partition on another.

I was baffled as to how Windows could see two different physical disks as one drive. Very much my bad.

Django Reinhardt

Posted 2014-04-24T15:25:48.783

Reputation: 4 183

Edit: This refers to disks 2/3 in op's original screenshot.

It probably is two different physical disks. In Windows 8+ dynamic disks can span multiple physical drives, yet still be addressed with one drive letter:

http://windows.microsoft.com/en-gb/windows-vista/what-are-basic-and-dynamic-disks

Dynamic disks can contain a large number of dynamic volumes (approximately 2000) that function like the primary partitions used on basic disks. In some versions of Windows, you can combine separate dynamic hard disks into a single dynamic volume (called spanning), split data among several hard disks (called striping) for increased performance, or duplicate data among several hard disks (called mirroring) for increased reliability.

RJFalconer

Posted 2014-04-24T15:25:48.783

Reputation: 9 791

I've updated my question. I think it was originally confusing, making it sound like I was wondering about my RAID array, which I'm not. Thanks. – Django Reinhardt – 2014-04-24T16:52:15.950