Can I have both Windows dynamic disk partition and some other non-Windows partition on the same disk?

When a basic Windows disk is converted to dynamic, Windows creates a partition that span the whole disk with the type of "Windows LVM" and manages its dynamic partitions within this space. So even if there is still free space on this disk, it is not visible to any other OS besides Windows. This happens with MBR and GPT disks both.

I would like to share a Windows dynamic disk with some other OS. I have to have dynamic disks because I use Windows SoftRaid (mirrors). So, my questions are:

Is there any way to "force" Windows to take up less then the whole disk when it converts a basic disk to dynamic?
Will Windows tolerate having some other non-Windows partition on its dynamic disk?

haimg

Posted 2012-08-31T02:56:27.780

Reputation: 19 503

Answers

If your computer's hardware supports it, using the motherboard's disk controller to do the RAID controlling would work better than using Windows' softare RAID controller. This will allow you to partition it like a normal drive. Alternatively, you could purchase a hardware RAID controller if it's in your budget.

It does appear that it's possible to force Linux to recognize your array, but I don't know how reliable that is. From my understanding, it is not possible to shrink the dynamic disk, but using a method like that, you may be able to have non-Windows partitions on the dynamic disk.

ND Geek

Posted 2012-08-31T02:56:27.780

Reputation: 802

This is a nice and reasonable advice. However, it does not answer my question. – haimg – 2012-08-31T04:19:31.620

I wasn't originally aware of any way to "share" software RAID between OSes, but I did some searching just now and it does appear to be possible. I added a link to a blog post to my answer that discusses it. I don't know how reliable it is, but it's a start. – ND Geek – 2012-08-31T13:12:26.330

Thank you, this is interesting. I asked about sharing the physical disk however, e.g. having an exta non-Windows partition on the same disk besides the Windows LDM partition, not accessing Windows dynamic disk partitions from Linux. – haimg – 2012-08-31T14:16:16.963

Ah sorry, I've been misunderstanding. To answer your questions directly, no, it is not possible to force Windows to partially use a disk for dyanamic disks. If Linux is able to use the dynamic disk array, it should be able to write its own partition to it, but I don't know if that's actually possible. If it is, Windows would likely ignore the Linux partition(s), just as it would with a physical disk partitioned to something other than FAT or NTFS. – ND Geek – 2012-08-31T15:46:42.150

The issue is that the disk is being labeled as dynamic, not a partition. You would not be able to make Windows use less space, as it is not a function of space. If you could do this, you would be breaking the functionality of the dynamic disk.

Keltari

Posted 2012-08-31T02:56:27.780

Reputation: 57 019

There is no such thing as "disk being labeled as dynamic". Internally, Windows creates an LDM partition that spans the whole disk. See, for example, http://en.wikipedia.org/wiki/Logical_Disk_Manager#Partition_table_types.

– haimg – 2012-08-31T04:17:35.650