Two drives failed in a production server, and one of the drives had already failed earlier. The server used RAID 6, so the array was beyond its normal fault tolerance. I replaced three drives and allowed the RAID controller to bring the array back online. The files and directories are visible, but the VHDX files stored on the array are corrupted and will not boot or mount.
The server and virtual machines run Windows Server 2012 R2 with Hyper-V. Attempting to attach a VHDX reports that adding the Microsoft Hyper-V virtual hard disk device failed, and mounting the files directly reports that they are corrupted. The original virtual machines also fail to start. I have a backup, but it is about a month old. Is there a safe way to repair or recover the VHDX files, or should I go straight to professional data recovery?
2 Answers
A VHDX repair utility such as qemu-img can inspect the disk image and, in some cases, create a repaired copy. Do this only on a duplicate, never the original. First verify the RAID layout and image integrity, then work from read-only copies. If the VHDX header or block allocation data is missing because of RAID corruption, software repair may not be able to reconstruct it.
If the files cannot mount on another Windows host and Hyper-V also rejects them, the problem is probably deeper than a normal boot issue. Restore the month-old backup if you need the service online, then attempt recovery from cloned images or consult a specialist. Do not repeatedly mount, repair, or rebuild the originals, since those operations can reduce the chances of recovering the remaining data.
The backup is available, but it is roughly a month old. I will use it for continuity while treating the newer VHDX files as a recovery case rather than continuing to modify the damaged array.