Three drives failed in a production server's RAID 6 array—the first failure happened before I joined the organization, and two more drives later died. I brought the array back online by replacing the failed drives and allowing it to rebuild, and I can browse the recovered data. However, the VHDX files stored on the array are corrupted and the virtual machines will not boot. Windows cannot mount the VHDX files, adding them to another Hyper-V host fails with a virtual disk device error, and booting them from the original server also fails. The host and guest systems are running Windows Server 2012 R2. A backup exists, but it is about a month old. Is there a reliable way to repair or extract data from these VHDX files, or should I stop working on the array and use a professional recovery service?
3 Answers
The exact error and the VHDX’s condition matter. Since Windows reports the virtual disk as corrupted and it will not mount, this is more than a Hyper-V boot configuration issue. You can inspect a copy with tools such as qemu-img, which may identify the virtual disk format problems and expose limited repair options, but do not run repair commands against the only copy.
If the VHDX cannot be mounted on another Windows system, the safest practical option is usually restoring the virtual machines from a current backup. The month-old backup may be the best recoverable version unless the damaged files contain critical newer data. Repeatedly attempting repairs on the original array can overwrite metadata and make professional recovery harder.
Before trying repairs, make forensic clones or image copies of every remaining drive and work only from those copies. If the array was forced online or rebuilt after three drives had failed, the data may already contain unrecoverable blocks or incorrect parity. A RAID recovery specialist may be able to help, especially if the two recently failed drives can still be read and cloned, but a complete recovery is far from guaranteed.
The array was brought back online by replacing three drives and letting it rebuild. I can browse the files, but the VHDX files themselves remain unusable.