Bug 676750

Summary:	internal snapshot lost when start guest with snapshot=on
Product:	Red Hat Enterprise Linux 6	Reporter:	Shirley Zhou <szhou>
Component:	qemu-kvm	Assignee:	Kevin Wolf <kwolf>
Status:	CLOSED WONTFIX	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	6.1	CC:	mkenneth, mshao, ndai, tburke, virt-maint
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-05-31 13:21:10 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:
Bug Blocks:	580951

Description Shirley Zhou 2011-02-11 02:51:26 UTC

Description of problem:
Start guest with snapshot=on mode, find previous internal snapshot disappear when check using "(qemu) info snapshot".

Version-Release number of selected component (if applicable):
qemu-kvm-0.12.1.2-2.144.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1.start guest, and save internal snapshot
(qemu) savevm test
(qemu) info snapshots 
Snapshot devices: drive-ide0-0-0
Snapshot list (from drive-ide0-0-0):
ID        TAG                 VM SIZE                DATE       VM CLOCK
1         test                    10M 2011-02-11 10:49:36   00:00:08.719

2.shutdown guest, and start with snapshot=on mode
-drive file=/dev/vgtest/lvtest,if=none,id=drive-ide0-0-0,format=qcow2,cache=none,snapshot=on

3. check snapshot again
(qemu) info snapshots 
Snapshot devices: drive-ide0-0-0
Snapshot list (from drive-ide0-0-0):
ID        TAG                 VM SIZE                DATE       VM CLOCK

  
Actual results:
snapshot disappear.

Expected results:
snapshot should be available.

Additional info:

Comment 2 Kevin Wolf 2011-02-17 13:29:53 UTC

Is this reproducible with -145?

Comment 3 Shirley Zhou 2011-02-18 02:27:23 UTC

(In reply to comment #2)
> Is this reproducible with -145?
Can be reproduce this issue with qemu-kvm-0.12.1.2-2.145.el6.x86_64.

Comment 5 Kevin Wolf 2011-05-31 13:21:10 UTC

I wonder why I asked for reproduction back in February... This can't work because snapshot=on creates a new qcow2 file with the image as a backing file, and neither can you load an internal snapshot from a backing file nor is it easy to implement. This would be a major RFE and we don't support internal snapshots. Closing.