Windows Server 2019 deployment ignores RAID 1 layout (Packer-built image)

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Hi everyone,

I’m facing an issue regarding storage layouts when deploying Windows Server 2019.

Environment:

  • MAAS Version: 3.4 (or your current version)

  • OS: Windows Server 2019 Standard

  • Image Build: Custom image created via packer-maas (curtin-based).

  • Hardware: Server with 2x 480GB SSDs.

The Issue: In the MAAS Web UI, I configured the machine’s storage layout as RAID 1 using both disks. The deployment completes successfully without any errors in the logs. However, once I log into the Windows instance and check Disk Management, the disks are not mirrored.

Instead, I see:

  • Disk 0: Fully partitioned with Windows (C:), Recovery, and EFI.

  • Disk 1: Unallocated / Not Initialized.

It seems the curtin installer is not translating the RAID 1 layout defined in MAAS into a Windows Dynamic Disk mirror or a compatible storage pool during the deployment phase.

Steps taken:

  1. Defined RAID 1 in the MAAS storage tab for the node.

  2. Verified that both disks are recognized by MAAS.

  3. Deployed the Windows 2019 image.

  4. Result: Windows boots from a single drive, ignoring the second drive entirely.

Questions:

  1. Does the current curtin installer support creating Windows native software RAID (Dynamic Disks or Storage Spaces) automatically?

  2. Is there a specific configuration needed in the curtin_userdata or within the Packer template to ensure the mirror is established during install?

  3. Should I be using a hardware RAID controller instead for Windows deployments in MAAS to ensure the OS sees a single logical volume?

Any insights or workarounds would be greatly appreciated.

Best regards,