Problem with opennebula and qcow2 images

Hello

This is really important for us .
we have a server with a persistent datablock with 200gb of space used as mysql datadir
3days ago our machine got into a problem and crashed so we shutdown the machine and start a new one with that persistent image but now the image is just 8GB and has a Installed os on that . opennebula database still tell us its persistent and has 200gb data by qemu img said:

qemu-img info /var/lib/one/gluster/145/1f73fdd57169fee71c652d0a717b6df4
image: /var/lib/one/gluster/145/1f73fdd57169fee71c652d0a717b6df4
file format: qcow2
virtual size: 8.0G (8589934592 bytes)
disk size: 867M
cluster_size: 65536
backing file: /var/lib/one/gluster/145/e639fa33f8ab49f7ed907c062d4899ef
Format specific information:
    compat: 1.1
    lazy refcounts: false

qemu check :
qemu-img check /var/lib/one/gluster/145/1f73fdd57169fee71c652d0a717b6df4
No errors were found on the image.
13850/131072 = 10.57% allocated, 5.75% fragmented, 0.00% compressed clusters
Image end offset: 908918784

its a 40gb database and now gone …
first i want to know what happend so how can i retrive the logs from db or …
second how can i recover my files its very important

now i can boot the images and has operating system installed exactly like first hdd mounted as os , i hope this is some miss configuration in addressing the image and i hope my image still some where

thanks its very important and urgent for me

It’s strange that the persistent disk has a backing file. Anyway, was the previous VM also using a persistent image and is that image the same as the new one? Are you using glusterfs driver or shared/qcow2? You can get information about the disks with:

$ onevm show -x <old vm id>

In case the old persistent disk is different check if it has the data. Persistent images are not deleted as they reside in the images datastore.