Bug 1349895

Summary:	libvirt should allow identical serial numbers for disks
Product:	[Fedora] Fedora	Reporter:	Dan Horák <dan>
Component:	libvirt	Assignee:	Libvirt Maintainers <libvirt-maint>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	24	CC:	agedosier, berrange, clalancette, crobinso, dyuan, itamar, laine, libvirt-maint, pkrempa, pzhang, veillard, virt-maint
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:	libvirt-1.3.3.2-1.fc24	Doc Type:	If docs needed, set a value
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Clone Of:		Environment:
Last Closed:	2016-07-22 15:57:45 UTC	Type:	Bug
Regression:	---	Mount Type:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description Dan Horák 2016-06-24 13:16:39 UTC

With recent libvirt it is not possible to create a domain where 2 virtual disks backed by the same image share the same serial number. I guess it is because of bug 1245013. But there is a strong use case for it - testing multipath storage setup without requiring external, possibly expensive, multipath capable storage, read for example http://sharkcz.livejournal.com/12846.html

It still works in libvirt-1.2.18.1-2.fc22 but not in libvirt-1.3.3.1-3.fc24

Comment 1 Daniel Berrangé 2016-06-24 13:35:29 UTC

Agreed, that is a valid use case and libvirt should not have tried to block it. We should revert all the patches from that referenced bug.

Comment 2 Cole Robinson 2016-06-24 13:38:12 UTC

CCing pkrempa who provided the patches for bug 1245013

Comment 3 Dan Horák 2016-06-24 13:54:15 UTC

Maybe it's just some logic missing to allow "my" use case, but still provide higher safety for regular users.

Comment 4 Daniel Berrangé 2016-06-24 13:56:14 UTC

It is generally not libvirt's job to impose policy decisions like this, unless it is functionally required by the virtualization layer. Even in real physical hardware you can attach 2 disks with the same serial - i've had cheap USB HDDs which did this.

Comment 5 Peter Krempa 2016-06-24 15:31:58 UTC

I agree. I wasn't aware of the necessity to have identical IDs. Since it doesn't pose any problems I've reverted both the serial and WWN check:

commit 5da28cc3069b573f54f0bcaf8eb75476bcfdc6e9
Author: Peter Krempa <pkrempa>
Date:   Fri Jun 24 17:01:27 2016 +0200

    conf: Allow disks with identical WWN or serial
    
    Disallowing them broke a use case of testing multipath configurations
    for storage. Originally this was added as it was impossible to
    use certain /dev/disk-by... links but the disks worked properly.

Comment 6 Fedora Update System 2016-07-19 11:24:50 UTC

libvirt-1.3.3.2-1.fc24 has been submitted as an update to Fedora 24. https://bodhi.fedoraproject.org/updates/FEDORA-2016-65cc608ebe

Comment 7 Fedora Update System 2016-07-20 01:53:28 UTC

libvirt-1.3.3.2-1.fc24 has been pushed to the Fedora 24 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2016-65cc608ebe

Comment 8 Fedora Update System 2016-07-22 15:56:39 UTC

libvirt-1.3.3.2-1.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.