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Bug 670162

Summary: [RFE] Removing the backing file using qemu-img re-base
Product: Red Hat Enterprise Linux 6 Reporter: Kevin Wolf <kwolf>
Component: qemu-kvmAssignee: Kevin Wolf <kwolf>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 6.1CC: abaron, areis, bsarathy, jkt, juzhang, lihuang, lnovich, lpeer, minovotn, mkenneth, qzhang, shu, sluo, szhou, tburke, virt-maint
Target Milestone: rcKeywords: FutureFeature, Reopened
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: qemu-kvm-0.12.1.2-2.369.el6 Doc Type: Enhancement
Doc Text:
New feature for removing the backing file using qemu-img rebase command has been implemented, this means that backing file won't be necessary but no data loss will occur when writing the rebase command.
 Story Points: ---
Clone Of: 576121 Environment:
Last Closed: 2013-11-21 05:42:42 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: 576121    
Bug Blocks: 580954, 756082    

Comment 16 Shaolong Hu 2013-06-24 06:07:53 UTC 
Verified on qemu-kvm-0.12.1.2-2.375.el6.x86_64:

1.
[root@localhost ~]# qemu-img create -f qcow2 base 10G
Formatting 'base', fmt=qcow2 size=10737418240 encryption=off cluster_size=65536 

[root@localhost ~]# qemu-img create -F qcow2 -f qcow2 -b base sn1 10G
Formatting 'sn1', fmt=qcow2 size=10737418240 backing_file='base' backing_fmt='qcow2' encryption=off cluster_size=65536 

[root@localhost ~]# qemu-img create -F qcow2 -f qcow2 -b sn1 sn2 10G
Formatting 'sn2', fmt=qcow2 size=10737418240 backing_file='sn1' backing_fmt='qcow2' encryption=off cluster_size=65536 

2.
[root@localhost ~]# qemu-img rebase -F qcow2 -f qcow2 -b base sn2

[root@localhost ~]# qemu-img info sn2
image: sn2
file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 196K
cluster_size: 65536
backing file: base

3.
[root@localhost ~]# qemu-img rebase -F qcow2 -f qcow2 -b "" sn2

[root@localhost ~]# qemu-img info sn2
image: sn2
file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 196K
cluster_size: 65536
Comment 20 errata-xmlrpc 2013-11-21 05:42:42 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2013-1553.html