Bug 800303

Summary:	libvirt running domain create snapshot take time over 7 mins
Product:	Red Hat Enterprise Linux 7	Reporter:	Huang Wenlong <whuang>
Component:	libvirt	Assignee:	Eric Blake <eblake>
Status:	CLOSED DUPLICATE	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.0	CC:	cwei, dallan, dyuan, mzhan, rwu, zhpeng
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:	2012-03-20 14:31:14 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:	799508

Description Huang Wenlong 2012-03-06 09:24:56 UTC

Description of problem:
 libvirt running domain create snapshot take time over 7 mins


Version-Release number of selected component (if applicable):
libvirt-0.9.7-3.el7.x86_64
qemu-kvm-0.15.1-3.2.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. start a domain and login the guest system
#virsh start rl62
2.
# time virsh snapshot-create rl62
 Domain snapshot 1331018776 created

real    7m1.991s
user    0m0.005s
sys    0m0.004s


3.

Actual results:
over 7 mins

Expected results:
in the rhel6 it is less than 1 min

Additional info:

Comment 1 Eric Blake 2012-03-20 14:31:14 UTC

This is the same problem as in bug 771626.  You are executing a system checkpoint internal snapshot, which includes RAM state, requires a convergence algorithm, and which requires lots of disk space in the qcow2 file (which takes time, especially if the qcow2 file has to grow in size to hold that much state).  But that is not a supported RHEL feature.  You should really be using the --disk-only option when you create snapshots, as that is MUCH faster, and _is_ supported for RHEV.

*** This bug has been marked as a duplicate of bug 771626 ***