Description of problem:
  When resume a VM from suspend, the VM always restart the operate system which cause the lose of the live memory that should be recorded after resuming.
     
Version-Release number of selected component (if applicable):
  vdsm-4.30.13-1.el7

How reproducible:
  Always

Steps to Reproduce:
1. Create a VM on cluster based on iscsi/FC.
2. Open some files in VM.
3. Click pause button on Ovirt UI to pause the VM.
4. Click run button to resume the VM from the suspend status .

Actual results:
   The VM restart OS, and enter an initialed state, no files opened.

Expected results:
   The VM resumed, and the files opened still be there in VM.

Additional info:
1. the vdsm reports an exception:
2019-05-09 08:42:39,705+0800 ERROR (vm/f060e3d3) [virt.vm] (vmId='f060e3d3-fc16-463c-bfe4-46c63ddfe97e') The vm start process failed (vm:937)
10714 Traceback (most recent call last):
10715   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 866, in _startUnderlyingVm
10716     self._run()
10717   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 2828, in _run
10718     self._connection.restore(fname)
10719   File "/usr/lib/python2.7/site-packages/vdsm/common/libvirtconnection.py", line 131, in wrapper
10720     ret = f(*args, **kwargs)
10721   File "/usr/lib/python2.7/site-packages/vdsm/common/function.py", line 94, in wrapper
10722     return func(inst, *args, **kwargs)
10723   File "/usr/lib64/python2.7/site-packages/libvirt.py", line 4513, in restore
10724     if ret == -1: raise libvirtError ('virDomainRestore() failed', conn=self)
10725 libvirtError: internal error: Child process (gzip -dc) unexpected exit status 2:
10726 gzip: stdin: decompression OK, trailing garbage ignored
10727 
10728 2019-05-09 08:42:39,705+0800 INFO  (vm/f060e3d3) [virt.vm] (vmId='f060e3d3-fc16-463c-bfe4-46c63ddfe97e') Changed state to Down: internal error: Child process (gzip -dc) unexpected exit status 2:
10729 gzip: stdin: decompression OK, trailing garbage ignored
10730  (code=1) (vm:1675)
10731 2019-05-09 08:42:39,710+0800 INFO  (vm/f060e3d3) [virt.vm] (vmId='f060e3d3-fc16-463c-bfe4-46c63ddfe97e') Stopping connection (guestagent:455)
2. This problem only happened on iscsi/FC storage, not NFS.
3. It seems that the problem is related with the bug: https://bugzilla.redhat.com/show_bug.cgi?id=1503468
   After I changed the config of save_image_format="lzop" in /etc/libvirt/qemu.conf, the problem  disappared. I think the reason is Comment 45 in above bug(1503468). 
    if it's not a problem, how should i do to avoid the problem?