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Bug 709656

Summary:	qemu-img snapshot creation failed with RHEL5.4KVM
Product:	Red Hat Enterprise Linux 5	Reporter:	Suresh Kolsur <kolsur>
Component:	kvm	Assignee:	Kevin Wolf <kwolf>
Status:	CLOSED WONTFIX	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	5.4	CC:	Jes.Sorensen, jon.benedict, juzhang, mkenneth, rhod, virt-maint
Target Milestone:	rc
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-07-28 14:39:25 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	580948

Description Suresh Kolsur 2011-06-01 10:12:44 UTC

Description of problem:

Tried using the qemu-img binary to create a snapshot of qcow2 image when VM is not running, but fails to create snapshot.

#qemu-img info test_8G.qcow2
image: test_8G.qcow2
file format: qcow2
virtual size: 8.0G (8589934592 bytes)
disk size: 2.5G
cluster_size: 4096

Version-Release number of selected component (if applicable):

RHEL Version:Red Hat Enterprise Linux Server release 5.4 (Tikanga)
KVM Version:kvm-83-105.el5
qemu-img binary version: 0.9.1
QEMU PC emulator version: 0.9.1 (kvm-83-maint-snapshot-20090205)

How reproducible:

#qemu-img snapshot -c testsnap test_8G.qcow2

qemu-img binary process is running for long time(> 10 min) and is not creating a snapshot.

# qemu-img snapshot -l test_8G.qcow2
#

Steps to Reproduce:
1. create a qcow2 image and install a VM on that.
2. using qemu-img snapshot -c; try to create a snapshot of the VM
3. Above with fail to create with out throwing any Error.
  
Actual results:
There is no snapshot of the VM created.

Expected results:
Expected to have a snapshot of the VM created

Additional info:

Comment 1 Kevin Wolf 2011-07-28 14:39:25 UTC

Please use external snapshots instead, i.e. create a new image that references test_8G.qcow2 as its backing file and use this image to run your VM:

qemu-img create -f qcow2 -b test_8G.qcow2 -F qcow2 test_8G_cow.qcow2