You added a second hardware RAID-5 array and want to mirror the original RAID-5 volume for full redundancy in Windows. The option to create a mirrored volume is unavailable on the new array. What must you do first?

Introduction / Context:
Windows 2000 and later can provide software fault tolerance by mirroring (RAID-1) at the volume level. However, the ability to create mirrored volumes requires the disks to use the dynamic disk type (managed by the Logical Disk Manager), not basic disks. When underlying storage is already hardware RAID, Windows sees each array as a single disk; you can still mirror volumes between them using dynamic disks.

Given Data / Assumptions:

• Two separate hardware RAID-5 arrays are visible as two disks in Windows.
• You want to mirror the volume on the original array to the new array.
• Disk Management does not show the mirror option for basic disks.

Concept / Approach:
Convert both disks from basic to dynamic using Disk Management. Only dynamic disks support creating mirrored volumes (and other dynamic volume types). Once converted, you can add a mirror to the existing simple volume (which sits atop the hardware RAID) so Windows keeps an identical copy on the second array. Partitioning or formatting steps on the new array are not prerequisites for enabling the Add Mirror function.

Step-by-Step Solution:

Verification / Alternative check:
After conversion and mirror creation, Disk Management should display the volume as “Mirrored” with both plexes healthy. Test by temporarily taking one array offline (in a controlled maintenance window) and verifying continuity.

Why Other Options Are Wrong:

• Create partitions/format: not required to expose the mirror option.
• Extended/logical: layout choice does not enable mirroring on basic disks.

Common Pitfalls:
Confusing hardware RAID with Windows dynamic disk mirroring; attempting to mirror while disks remain basic; overlooking backups before conversion (conversion is nondestructive but precautions are recommended).

Final Answer:
Convert both to dynamic disks.