Bug 1551684

Summary:	[CodeChange][Tracking] Map and remove vdsm flows that needlessly prepare the entire chain
Product:	[oVirt] vdsm	Reporter:	Allon Mureinik <amureini>
Component:	Core	Assignee:	Dan Kenigsberg <danken>
Status:	CLOSED DEFERRED	QA Contact:	Avihai <aefrat>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	4.20.19	CC:	bugs
Target Milestone:	---	Keywords:	CodeChange, Improvement, Performance, Tracking
Target Release:	---	Flags:	rule-engine: ovirt-4.3+
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-04-01 14:47:46 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:	1395941
Bug Blocks:

Description Allon Mureinik 2018-03-05 17:43:25 UTC

Description of problem:
qemu-img-[[rh]ev]-2.10 provided the ability to perform "unsafe" operations on the leaf of a qcow2 chain, without preparing the entire backing chain (see bug 1213786) for details.

This BZ is a tracker for mapping out places where vdsm needlessly prepares the entire chain and fixing them so they prepare the minimal number of volumes, if at all.
Fixing these would both improve performance and reduce the risk of leaving "leftover" prepared volumes they may later cause problems.

Version-Release number of selected component (if applicable):
vdsm-4.20

An initial list of flows to consider:
- Creating a snapshot (already handled by bug 1395941).
- Creating a thin VM/pool on top of a snapshot (possibly handled by the previous item)
- Merging a snapshot (only the two volumes merged should be activated, at least in theory)
- Amending qcow compat level
- Extending the size of a disk
- getVolumeInfo
-

Comment 2 Sandro Bonazzola 2019-01-28 09:37:02 UTC

This bug has not been marked as blocker for oVirt 4.3.0.
Since we are releasing it tomorrow, January 29th, this bug has been re-targeted to 4.3.1.

Comment 3 Michal Skrivanek 2020-03-18 15:46:43 UTC

This bug didn't get any attention for a while, we didn't have the capacity to make any progress. If you deeply care about it or want to work on it please assign/target accordingly

Comment 4 Michal Skrivanek 2020-03-18 15:51:29 UTC

This bug didn't get any attention for a while, we didn't have the capacity to make any progress. If you deeply care about it or want to work on it please assign/target accordingly

Comment 5 Michal Skrivanek 2020-04-01 14:47:46 UTC

ok, closing. Please reopen if still relevant/you want to work on it.

Comment 6 Michal Skrivanek 2020-04-01 14:51:11 UTC

ok, closing. Please reopen if still relevant/you want to work on it.