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I have a Dell R720 server running Windows Server Datacenter 2022, and the disk containing the operating system has bad tracks that spread over time.

To migrate the OS,

  • I used DiskGenius to clone all valid data sectors from the damaged disk to a new SSD.
  • I then removed the old disk,
  • inserted the new one into the same slot,
  • and added it to the H710 RAID controller.

But the system still couldn't boot from it, showing a no boot device available error.

The cloning process had some errors due to bad tracks, but I expected the new SSD to be identical to the old one, including the boot partition.

Some additional information that might help to address this problem:

  • the OS uses Legacy(BIOS) boot instead of UEFI boot.
  • Both disks are SSDs with the same capacity. The old one is Samsung EVO 870 and the new one is Crucial MX500.
  • The disk contains 4 primary partitions, one for boot, one for the OS, one for software, and one for the database.
Rohit Gupta
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1 Answers1

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Legally required notice: I work for Dell.

You can’t clone a disk with an OS and expect it to boot. There are a variety of reasons for this. It is not correct to assume to drives of the same size behave identically. Under the hood NVMe drives are very complex beasts with their own processor, memory, and what is effectively a RAID.

Your cloned bootloader would need to align such that the BIOS finds the MBR at exactly the same physical place. Additionally, since you’re using MBR, it records physical addresses in the partition table rather than logical and that means all your partitions would have to be assigned to exactly the same physical addresses for this to work.

As you have discovered, cloning just copies the data. That doesn’t mean the data was assigned to the same physical addresses.

Physical addresses are determined by the disk’s internal geometry which vary within vendors and especially between two completely different drives from two completely different vendors.

The original partitions should still be intact so I’d back that stuff up elsewhere and then reinstall the OS. You could try to manually repair it but that’s probably wasted time unless you find it an interesting academic exercise.

Edit: there are tools out there that might automatically fix all those addresses for you. I haven’t used them in ages but they were hit and miss for me. I don’t know about the one you used but clearly the results were that it didn’t. I say this more to the point that it can be done in an automated way but in my personal experience with those things it’s error prone.

Edit 2: if this was part of a RAID and not pass through then it most definitely won’t work for much the same reasons.

Grant Curell
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