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Type: Story
Resolution: Unresolved
Priority: Major
Fix Version/s: rhel-9.4
Affects Version/s: rhel-9.0.0
Component/s: libvirt / Storage
Labels:

Fixed in Build:
libvirt-9.10.0-1.el9
Severity:
Major
Epic Link:
Default to external snapshots in virsh

Pool Team:

sst_virtualization_storage
Sub-System Group:

ssg_virtualization

Dev Target Milestone:
13
Internal Target Milestone:
23
ACKs Check:

QE ack, Dev ack
Blocked:
False
Blocked Reason:

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None

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None

Preliminary Testing:
Pass
Test Link:
https://polarion.engineering.redhat.com/polarion/#/project/RHELVIRT/workitem?id=VIRT-300072
Errata Link:
https://errata.devel.redhat.com/advisory/125049
Test Coverage:

Yes

Release Note Type:
Enhancement
Release Note Text:

Hide
.External snapshots for virtual machines

This update introduces the external back-end mechanism for virtual machine (VM) snapshots, which replaces the previously deprecated internal snapshot mechanism. As a result, creating and reloading VM snapshots is now fully supported and works more reliably both in the command-line interface and in the RHEL web console. This also applies to snapshots of running VMs, also known as live snapshots.

For more information, see Managing virtual machine snapshots in RHEL 9 <TODO add link to virt guide when it's ready>.

Show
.External snapshots for virtual machines This update introduces the external back-end mechanism for virtual machine (VM) snapshots, which replaces the previously deprecated internal snapshot mechanism. As a result, creating and reloading VM snapshots is now fully supported and works more reliably both in the command-line interface and in the RHEL web console. This also applies to snapshots of running VMs, also known as live snapshots. For more information, see Managing virtual machine snapshots in RHEL 9 <TODO add link to virt guide when it's ready>.
Release Note Status:
In Progress

Architecture:

Unspecified
Target Upstream Version:
9.9.0
Bugzilla Bug:
RHBZ: 1519002

SFDC Cases Counter:
SFDC Cases Links:

Description

+++ This bug was initially created as a clone of Bug #1402581 +++

Description of problem:
For historical reasons, 'virsh snapshot-create' defaults to internal snapshots, because external snapshots were not implemented for several years. However, these days the qemu team recommends the use of external snapshots, and upper levels like RHEV prefer external snapshots. It would be nice if there were a way to set up configuration defaults for virsh, so that typing 'virsh snapshot-create' could consult the configuration file on whether to default to internal or external, instead of forcing the user to remember to pass extra flags to get an external snapshot.

Version-Release number of selected component (if applicable):
libvirt-2.5.0-1.el7

How reproducible:
100%

Steps to Reproduce:
1.
2.
3.

Actual results:

Expected results:

Additional info:

— Additional comment from Laszlo Ersek on 2017-02-24 20:50:15 BRT —

When designing this feature for virsh (and virt-manager), please don't forget about the UEFI varstore files (under /var/lib/libvirt/qemu/nvram), which are technically raw drives, but have very different storage properties from normal drives. They don't live in storage pools, they are not on shared storage, and also not subject to storage migration. QEMU automatically writes them out fully on the target host after migration finishes.

I'm unsure how this interacts with external snapshots, but I figure I'd better raise it. Thanks.