Bug 1256500
| Summary: | [RFE][scale] Snapshot deletion of poweredoff VM takes longer time. | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Virtualization Manager | Reporter: | Amador Pahim <asegundo> |
| Component: | ovirt-engine | Assignee: | Ala Hino <ahino> |
| Status: | CLOSED ERRATA | QA Contact: | Raz Tamir <ratamir> |
| Severity: | medium | Docs Contact: | |
| Priority: | high | ||
| Version: | 3.5.3 | CC: | ahino, amureini, asegundo, bmcclain, hkim, jcoscia, lsurette, mkalinin, nsoffer, ratamir, rbalakri, Rhev-m-bugs, srevivo, tnisan, trichard, ykaul, ylavi |
| Target Milestone: | ovirt-4.1.0-beta | Keywords: | FutureFeature |
| Target Release: | --- | Flags: | bmcclain:
priority_rfe_tracking+
gklein: testing_plan_complete- |
| Hardware: | All | ||
| OS: | Linux | ||
| URL: | https://github.com/alhino/ovirt-site/blob/29cf794c5c6b246e32ba41227e476a719ee894a8/source/develop/release-management/features/storage/remove-snapshot.html.md | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Enhancement | |
| Doc Text: |
Previously, deleting a snapshot while the virtual machine was down took a long time. With this release, snapshot deletion while a virtual machine is down uses 'qemu-img commit' instead of 'qemu-img rebase', improving the performance of the operation.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2017-04-25 00:48:59 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | Storage | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1246114 | ||
| Bug Blocks: | 1420198 | ||
Related to bug 1206328 (offline merge too slow). Amador, please add relevant customer cases so we can schedule this. Ala, please update the doc text with the feature page or a relevant text |
Currently the merge operation is very expensive and requires the equivalent storage space available for the _MERGE image. See the flow on removing snapshot1: (raw 10G) ------------------------ | ca8b5daa (snapshot1) | ------------------------ | (cow) | ------------ ---------| 00d83dd2 |---- ------------ | (active) | | qemu-img convert (raw 10G) | ------------------ <---------- | 00d83dd2_MERGE | ----------- ------------------ | | | rename (raw 10G) | ------------ | | 00d83dd2 | <--------------- ------------ (active) In consequence of the _MERGE image creation, storage can run out-of-space, since many users believe removing snapshots will free some storage space and they do that when the storage is close to the limit. The _MERGE volume is not desired at all in that scenario. Qemu has support for 'qemu-img commit', wich can commit the changes in a cow image to its backing file. After the commit, we can drop the cow image and use the backing file directly. Please change the offline merge method to use 'qemu-img commit' instead of the external merge image.