1025596 – Read/Randread/Randrw performance regression

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Bug 1025596 - Read/Randread/Randrw performance regression

Summary: Read/Randread/Randrw performance regression

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 6
Classification:	Red Hat
Component:	qemu-kvm
Sub Component:
Version:	6.5
Hardware:	x86_64
OS:	Linux
Priority:	urgent
Severity:	urgent
Target Milestone:	rc
Target Release:	---
Assignee:	Fam Zheng
QA Contact:	Virtualization Bugs
Docs Contact:
URL:
Whiteboard:
Depends On:	1022548
Blocks:
TreeView+	depends on / blocked

Reported:	2013-11-01 03:46 UTC by Jan Kurik
Modified:	2013-12-05 10:42 UTC (History)
CC List:	17 users (show)
Fixed In Version:	qemu-kvm-0.12.1.2-2.415.el6_5.2
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed:	2013-11-22 00:25:55 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2013:1750	0	normal	SHIPPED_LIVE	qemu-kvm bug fix update	2013-11-21 09:13:23 UTC

Description Jan Kurik 2013-11-01 03:46:11 UTC

This bug has been copied from bug #1022548 and has been proposed
to be backported to 6.5 z-stream (EUS).

Comment 9 Qunfang Zhang 2013-11-08 08:21:24 UTC

Test the following scenarios according to Kevin and Fam's suggestions on qemu-kvm-0.12.1.2-2.415.el6_5.1. But there's some problem in scenario (2).

(1) Internal snapshot with qcow2 => Pass.
a. Boot a guest with qcow2 format
b. Create internal snapshot 1 during the guest boot.
(qemu) savevm 1
c. Login guest after guest boot up and ping external host. Then create another internal snapshot
(qemu) savevm 2
d. (qemu) loadvm 1
c. (qemu) loadvm 2

Result: Internal snapshot could be created and loaded successfully.

(2)  qemu-img create -f vmdk -o subformat=monolithicFlat /tmp/a.vmdk 1G
Formatting '/tmp/a.vmdk', fmt=vmdk size=1073741824 compat6=off subformat='monolithicFlat' zeroed_grain=off 
[root@localhost home]# 
[root@localhost home]# 
[root@localhost home]# qemu-img info /tmp/a.vmdk 
image: /tmp/a.vmdk
file format: raw
virtual size: 0 (0 bytes)
disk size: 4.0K
[root@localhost home]# 

==> As a result, the file format is raw instead of "vmdk", and the virtual size is 0 instead of 1G.

Downgrade the qemu-kvm to qemu-kvm-0.12.1.2-2.415.el6, no this issue:

# rpm -qa | grep qemu
gpxe-roms-qemu-0.9.7-6.10.el6.noarch
qemu-img-0.12.1.2-2.415.el6.x86_64
qemu-kvm-0.12.1.2-2.415.el6.x86_64
qemu-kvm-debuginfo-0.12.1.2-2.415.el6.x86_64
qemu-kvm-tools-0.12.1.2-2.415.el6.x86_64 

[root@localhost qemu-kvm-415]#  qemu-img create -f vmdk -o subformat=monolithicFlat /tmp/b.vmdk 1G
Formatting '/tmp/b.vmdk', fmt=vmdk size=1073741824 compat6=off subformat='monolithicFlat' zeroed_grain=off 
[root@localhost qemu-kvm-415]# 
[root@localhost qemu-kvm-415]# 
[root@localhost qemu-kvm-415]# qemu-img info /tmp/b.vmdk
image: /tmp/b.vmdk
file format: vmdk
virtual size: 1.0G (1073741824 bytes)
disk size: 4.0K

Hi, Kevin and Fam

Could you help have a look at scenario (2)?  Is this a regression? 

Thanks,
Qunfang

Comment 10 Qunfang Zhang 2013-11-08 08:31:51 UTC

Change the status back to ASSIGNED according to comment 9, please help have a check and help fix it asap. Thanks a lot.

Comment 14 Qunfang Zhang 2013-11-12 07:18:56 UTC

Test the following scenarios on qemu-kvm-0.12.1.2-2.415.el6_5.2.x86_64, passed.

(1) Internal snapshot with qcow2 => Pass.
a. Boot a guest with qcow2 format
b. Create internal snapshot 1 during the guest boot.
(qemu) savevm 1
c. Login guest after guest boot up and ping external host. Then create another internal snapshot
(qemu) savevm 2
d. (qemu) loadvm 1
c. (qemu) loadvm 2

Result: Internal snapshot could be created and loaded successfully.

(2) #  qemu-img create -f vmdk -o subformat=monolithicFlat /tmp/a.vmdk 1G
Formatting '/tmp/a.vmdk', fmt=vmdk size=1073741824 compat6=off subformat='monolithicFlat' zeroed_grain=off 
[root@localhost home]# 
[root@localhost home]# qemu-img info /tmp/a.vmdk 
image: /tmp/a.vmdk
file format: vmdk  ==> This is correct.
virtual size: 1.0G (1073741824 bytes)
disk size: 4.0K



[root@localhost home]#  qemu-img create -f vmdk -o subformat=monolithicFlat /tmp/b.vmdk 100G
Formatting '/tmp/b.vmdk', fmt=vmdk size=107374182400 compat6=off subformat='monolithicFlat' zeroed_grain=off 
[root@localhost home]# 
[root@localhost home]# 
[root@localhost home]# qemu-img info /tmp/b.vmdk 
image: /tmp/b.vmdk
file format: vmdk  ==> This is correct.
virtual size: 100G (107374182400 bytes)
disk size: 4.0K

Besides, we will run performance test, function test (virtual block, glusterfs, storage vm migration, qcow2, vmdk) to verify this bug.

Comment 21 errata-xmlrpc 2013-11-22 00:25:55 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/RHBA-2013-1750.html

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