Attempting to download a Memory Dump from a VM results in an empty tar directory. 

4.12 and 4.13

On 4.12:

Create dump with: 
#virtctl memory-dump get rhel8-feqarbepxe4sgxcf --claim-name=shaggy-dump --create-claim


$oc describe vm rhel8-feqarbepxe4sgxcf 
   Memory Dump Request:
    Claim Name:       shaggy-dump
    End Timestamp:    2024-03-07T18:56:21Z
    File Name:        rhel8-feqarbepxe4sgxcf-shaggy-dump-20240307-185618.memory.dump
    Phase:            Completed
    Start Timestamp:  2024-03-07T18:56:18Z

$oc get pvc
NAME                     STATUS   VOLUME                                     CAPACITY      ACCESS MODES   STORAGECLASS   AGE
shaggy-dump              Bound    pvc-5c2b9e8e-cab3-42f0-b00d-06332072e5cb   2267Mi        RWO            nfs-client     35s


Download it with: 
#virtctl vmexport download shaggy-dump --pvc=shaggy-dump --volume=pvc-5c2b9e8e-cab3-42f0-b00d-06332072e5cb --output=shaggy.img.gz

However it looks to be empty? 
[kni@cee ~]$ tar -ztvf shaggy.img.gz
drwxrwxrwx root/root         0 2024-03-07 13:56 ./

On 4.13 using the all in one command:

$ virtctl memory-dump get rhel8-dumptest --create-claim --claim-name=dumptest --output=dumptest.tar.gz
PVC shaggy/dumptest created
Successfully submitted memory dump request of VM rhel8-dumptest
Waiting for memorydump  to complete, current phase: Associating...
Waiting for memorydump  to complete, current phase: InProgress...
Waiting for memorydump  to complete, current phase: InProgress...
Memory dump completed successfully
VirtualMachineExport 'shaggy/export-rhel8-dumptest-dumptest' created succesfully
Downloading file: 122 B [___________________] ? p/s                                                                                                                                                
Download finished succesfully
VirtualMachineExport 'shaggy/export-rhel8-dumptest-dumptest' deleted succesfully

$ tar -ztvf dumptest.tar.gz 
drwxrwxrwx virt-exportserver/107 0 2024-03-07 14:15 ./

Above downloaded dump is empty also


$oc describe vm rhel8-dumptest

  Memory Dump Request:
    Claim Name:       dumptest
    End Timestamp:    2024-03-07T19:15:36Z
    File Name:        rhel8-dumptest-dumptest-20240307-191534.memory.dump
    Phase:            Completed
    Start Timestamp:  2024-03-07T19:15:34Z


Attach dumptest pvc to vm in the GUI, stop VM, start VM 

[kni@cee ~]$ oc get pods -o wide
NAME                                 READY   STATUS    RESTARTS   AGE   IP            NODE                 NOMINATED NODE   READINESS GATES
hp-volume-9dkqd                      1/1     Running   0          7s    10.128.3.25   openshift-worker-1   <none>           <none>
virt-launcher-rhel8-dumptest-rs5pp   1/1     Running   0          10s   10.128.3.24   openshift-worker-1   <none>           1/1


oc debug node/openshift-worker-1 
we see the dump pvc mounted here on the host: 

sh-4.4# df | grep dumptest
192.168.111.1:/shaggy-rhel8-dumptest-pvc-0a340671-13fd-4e2e-b2ab-8b45d3bbf8a2 3669661696 326250496 3343411200   9% /host/var/lib/kubelet/pods/0d24eb5d-9f66-4262-99c1-d75b098fa144/volumes/kubernetes.io~nfs/pvc-0a340671-13fd-4e2e-b2ab-8b45d3bbf8a2
192.168.111.1:/shaggy-dumptest-pvc-d5a7ac30-5c00-4ab4-870c-b72effdce7e7       3669661696 326250496 3343411200   9% /host/var/lib/kubelet/pods/4434f45e-b5e7-47af-a148-a23ef5520edf/volumes/kubernetes.io~nfs/pvc-d5a7ac30-5c00-4ab4-870c-b72effdce7e7    


sh-4.4# cd /host/var/lib/kubelet/pods/4434f45e-b5e7-47af-a148-a23ef5520edf/volumes/kubernetes.io~nfs/pvc-d5a7ac30-5c00-4ab4-870c-b72effdce7e7
sh-4.4# ls -la
total 2113732
drwxrwxrwx. 2  107  107         65 Mar  7 19:15 .
drwxr-x---. 3 root root         54 Mar  7 19:17 ..
-rw-------. 1  107  107 2164458827 Mar  7 19:15 rhel8-dumptest-dumptest-20240307-191534.memory.dump

Here we see the file that we would need for the dump, so we know the dump was created successfully

Downloaded tar file is empty and only 122B

The tar file should contain the entire memory image and be approx 2GB to match the amount of memory