Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

Bug 2089434

Summary:	[RFE] RFE to allow enabling ZEROCOPY live migration
Product:	[oVirt] ovirt-engine	Reporter:	Nils Koenig <nkoenig>
Component:	BLL.Virt	Assignee:	Milan Zamazal <mzamazal>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Qin Yuan <qiyuan>
Severity:	high	Docs Contact:
Priority:	high
Version:	4.5.0.8	CC:	ahadas, bugs, dfodor, gveitmic, lrotenbe, lsvaty, mperina, mtessun, nkoenig, ymankad
Target Milestone:	ovirt-4.5.3	Keywords:	FutureFeature, OtherQA
Target Release:	---	Flags:	mperina: ovirt-4.5+ pm-rhel: planning_ack? mperina: devel_ack+ pm-rhel: testing_ack?
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	vdsm-4.50.3.1	Doc Type:	Enhancement
Doc Text:	The feature is described on its feature page: https://ovirt.org/develop/release-management/features/virt/zerocopy-migrations.html Note that the feature is not intended for common use, only for large VMs (>1 TB RAM) when the user is willing to accept the risk implied by the fact it is a new feature. The scope of support is waiting for clarification.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-12-05 12:46:45 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	Virt	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2117272
Bug Blocks:

Comment 1 Milan Zamazal 2022-06-09 12:29:37 UTC

We don't know yet what libvirt will provide, but the following strings from the QEMU source code are important: 

- "Zero copy only available for non-compressed non-TLS multifd migration". 
- "Requires that QEMU be permitted to use locked memory for guest RAM pages."

Translated to oVirt terms it means this feature can be used only with non-encrypted parallel-connections migrations and we may need to set memtune hard limit for all VMs, not just those with q35 and VFIO devices. It would be easiest to use this feature automatically whenever the given constraints are satisfied. The only reason, currently known to me, not to do it is that it is a new feature, which may have unanticipated issues. Alternatively, there could be an Engine config option to enable/disable support for this feature, or a parallel migration connections option.

Comment 8 Qin Yuan 2022-09-22 12:42:45 UTC

Verified with:
ovirt-engine-4.5.3-0.2.el8ev.noarch
vdsm-4.50.3.1-1.el8ev.x86_64
libvirt-8.0.0-5.4.module+el8.6.0+16370+bb85faee.x86_64

Steps:
Run the cases in the attached Polarion test plan.

Results:
All cases passed.

Comment 9 Nils Koenig 2022-11-22 13:29:29 UTC

What's the status this one, do you have an eta when it will end up in ovirt?

Comment 10 Milan Zamazal 2022-11-22 13:55:37 UTC

It's in oVirt 4.5.3 (and the corresponding RHV version).

Comment 11 Red Hat Bugzilla 2023-09-18 04:37:43 UTC

The needinfo request[s] on this closed bug have been removed as they have been unresolved for 120 days