vSAN storage and file download(6.7)

[rickyguy]

Recently, I encountered a problem while learning vsphere: I built a cluster in a vmware environment. In this cluster, there are 3 hosts, and I created a new virtual machine on the vsphere client management page. The storage of the virtual machine On vsanstorage, after the virtual machine was created, there was a sudden power outage, causing the virtual machine to fail to start again. I tried to download the vmdk file and found that this file was not a real virtual disk file, but a text file (The size is less than 1kb). Later, I searched for the corresponding topic on the Internet and found that someone had a similar situation to me. In other words, the original normal vmdk file was lost, and now I need to restore this vmdk file. After I learned what I was about to do, I found it to be very difficult because I didn't know how the actual vmdk file was stored. What if I need to try to retrieve this vmdk file manually?

[a_p_]

Please see whether https://kb.vmware.com/s/article/70726 helps to find the missing object.

André

[rickyguy]

Thanks,I'll try😄

[rickyguy]

Although this article is wonderful, but it wasn't very helpful to me. I can only view the object information, but there is no information about which disk these objects are on and the corresponding coordinate information. I will elaborate on the problems I encountered and the ideas I understand to solve the problem, which may help solve the problem.

Problem Details:

1. A virtual machine has become unbootable due to a sudden power outage.
2. The size of the VMDK virtual disk file appears normal.
3. I attempted to download the virtual disk file locally and then mount it, but the downloaded file was only a few hundred bytes and appeared as a text file.

The question is: In a normal virtual machine, when I download a virtual disk file from vsanstorage, I can see that the downloaded file is normal and is named "virtualmachine_stream.vmdk". Why do I get a completely different result when downloading the disk file of this unbootable virtual machine?

Then, I found some suggestions online indicating that I may need to manually recover the data from the virtual disk file. The general approach is as follows:

1. Use the value of the virtual object "vsan://uuid" in the VMDK file to locate the structure of that virtual object on the physical disk, as shown in the diagram below:

2. Based on the value of "vsan://uuid", navigate to the cluster and, under the [Monitoring] menu, select the [vSAN] item. Find and select the UUID, and then view the detailed placement location of the virtual object, as shown in the diagram below:

3. click 'View Placement Details'

in this picture, it shows the all objects associated with this virtual object,such as cache disk and capacity disk.

4. Up to now, I don't know how to proceed. However, someone said that I could clone the disk according to the information in the above picture, and then analyze the corresponding structure (similar to a certain file format), extract the metadata, and rebuild the virtual disk file. Finally, I can restore it. So, I want to know whether this method is feasible. If it is feasible, what technical details related to vsan storage should I further understand.

 

[a_p_ · Accepted solution]

I didn't need to go through this procedure myself yet.
However, from what I understand, the KB article shows the steps to find out whether the object/component is still available.
After making sure that the correct object/component has been identified, you may then proceed with creating the descriptor file, which is basically a pointer to that component's UUID.

Anyway, since you said that the descriptor file was still available, I'm afraid that the component somehow got lost.

Good luck.

André