Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.
RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Bug 1039557

Summary: optimize qemu-img for thin provisioned images
Product: Red Hat Enterprise Linux 7 Reporter: Paolo Bonzini <pbonzini>
Component: qemu-kvmAssignee: Paolo Bonzini <pbonzini>
Status: CLOSED CURRENTRELEASE QA Contact: Virtualization Bugs <virt-bugs>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 7.0CC: acathrow, juzhang, knoel, michen, pbonzini, sluo, virt-maint
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: qemu-kvm-1.5.3-31.el7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-06-13 12:49:51 UTC Type: Bug
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: 1007815    
Bug Blocks:    

Description Paolo Bonzini 2013-12-09 13:00:50 UTC
qemu-img is not able to use information from the image metadata (like the information in qemu-img map).  This information can be used to speed up conversion of images.

Example:
$ qemu-img create prova.img 1G
Formatting 'prova.img', fmt=raw size=1073741824 

Without feature:
$ time qemu-img convert -f raw -O raw -t none prova.img prova2.img
real	0m0.504s
user	0m0.129s
sys	0m0.347s

With feature:
$ time ./qemu-img convert -f raw -O raw -t none prova.img prova2.img
real	0m0.281s
user	0m0.002s
sys	0m0.009s

The effect is even more visible with the "-p" option to qemu-img.

Comment 3 Sibiao Luo 2014-01-21 06:10:21 UTC
Reproduce and verify this issue with the same steps as comment #0.

# qemu-img create prova.img 1G
Formatting 'prova.img', fmt=raw size=1073741824 
# qemu-img info prova.img 
image: prova.img
file format: raw
virtual size: 1.0G (1073741824 bytes)
disk size: 0

With the unfixed qemu-kvm version:
# rpm -q qemu-kvm
qemu-kvm-1.5.3-30.el7.x86_64

# time qemu-img convert -f raw -O raw -t none prova.img prova1.img

real	0m0.435s
user	0m0.058s
sys	0m0.308s

With the fixed qemu-kvm version:
# rpm -q qemu-kvm
qemu-kvm-1.5.3-38.el7.x86_64

# time qemu-img convert -f raw -O raw -t none prova.img prova2.img

real	0m0.024s
user	0m0.002s
sys	0m0.001s

Base on above, this issue has been fixed correctly. Move to VERIFIED status.

Best Regards,
sluo

Comment 4 Ludek Smid 2014-06-13 12:49:51 UTC
This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.