Windows – Linux volume on a Windows dynamic disk

partitioningwindows

MSDN says the following about changing drive types:

However, you can use dynamic disks with other operating systems, such as UNIX. To do this, you need to create a separate volume for the non-Windows operating system.

This implies Windows has a way of letting me create a plain old partition on a disk managed by Windows's Logical Disk Manager (LDM).

  • How is that achieved? How can I take a disk convered into a 'dynamic disk', slice a chunk of the space away from LDM, and create any type of regular GPT partition?

  • Alternatively, is is possible to go the other way around? I've already tried to create GPT partitions with relevant type GUIDs (one for LDM metadata and one for data) in order to provide a chunk of disk for Windows to use for LDM, but to no avail: Windows now sees the entire disk as an 'invalid dynamic disk' (but curiously manages to recognize an NTFS partition on the relevant disk and mounts it without problems; only diskmgmt.msc has issues).

I'm interested in using the rest of the disk for other operating systems, including a chunk being given to Linux's LVM.

Current situation

  • Two 3TB disks
  • Both contain one ~300GB Linux LVM partition (containing one LVM-managed mirrored volume) and one ~500GB HFS volume
  • First disk contains one ~300GB NTFS volume.
  • Both disks are currently 'basic'. (That is: normal, civilized GPT.)
  • Due to the type of these GPT partitions (LVM, HFS), converting the entire disks into dynamic disks is unsupported (and would make the partitions unreadable by other operating systems).

Desired situation

  • I'd like to devote ~300GB on both disks to Microsoft LDM
  • I'd like Microsoft LDM to manage just its chunk of the disk.
  • I would not like Microsoft LDM to even attempt to manage LVM partition (containing its LVM-managed ext3 volume) nor the HFS volume.

Why?

  • This is possible with LVM.
  • I'd like to avoid buying two additional Windows-dedicated disks just to get redundancy (mirroring is why I want LDM).
  • The paragraph quoted seems to imply that one can cut out a chunk of the disk and dedicate to "UNIX".
    • If one can dedicate just a portion of disk to LDM, that makes sense.
    • If one must dedicate the entire disk to LDM and is supposed to carve out a partition dedicated to "UNIX", that seems unreasonable, as "UNIX" would not be able to boot from an LDM-managed volume, or would damage it in LDM's eyes. (Especially if it is striped, but even if it is mirrored in any way.)
    • Because that is so unreasonable, I hope Microsoft did not mean: You can create an LDM-managed volume and boot "UNIX" off of this LDM-managed, possibly striped, volume.

Best Answer

Although the Windows Disk Management does not allow the resize of dynamic disks, some third party tools claim that ability.

Some of the better-known ones are :

EaseUS Partition Master (free) - see the article How to resize dynamic volume?
AOMEI Partition Assistant (Home version is free but unclear if can resize dynamic disks)
AOMEI Dynamic Disk Manager ($36 with trial)

If the tools can as advertised shrink the dynamic disk, the resulting unallocated space can be used in a new partition.

[EDIT1]

I still have the feeling you have it backward: I believe that the quoted Microsoft text meant that you create the dynamic disk over the entire physical disk, then allocate a volume in it and use that volume in a non-Windows OS.

Some recent Linux distributions understand dynamic disks, but I don't know to what degree. Otherwise you might need to find out which physical sectors are occupied by the volume(s) and mount in Linux as as a raw device (horrifying even if possible).

[EDIT2]

You wish for a separate RAID for Windows-only, which requires dynamic disks, which are a proprietary Windows format, not well-supported by Linux.

Below is an idea for another solution. This solution will require studying and trying - I have never done it and so can't offer a cookbook.

The idea is to use an advanced boot manager such as Grub4dos, that can hide/unhide partitions depending on the OS booted. It can also map partitions and do disk emulation. You might be able to use it to fool Windows into thinking that two partitions on two disks are each the entire disk (Windows will not see the rest of the disk), so you could set up dynamic disks on the two virtual disks without affecting Linux which will be using the rest of the physical disks.

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