Bug 957881

Summary:	lvconvert --merge support for a snapshot of a thinly provisioned LV
Product:	[Fedora] Fedora	Reporter:	Mike Snitzer <msnitzer>
Component:	lvm2	Assignee:	Zdenek Kabelac <zkabelac>
Status:	CLOSED RAWHIDE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	rawhide	CC:	agk, bmarzins, bmr, cmarthal, dwysocha, heinzm, jonathan, lvm-team, msnitzer, prajnoha, prockai, zkabelac
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	lvm2-2.02.105-1.fc21	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	1053586 (view as bug list)		Environment:
Last Closed:	2014-01-21 11:06:30 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	957875

Description Mike Snitzer 2013-04-29 19:17:37 UTC

Description of problem:
Add support for merging a snapshot into it's thinly provisioned origin volume.

Will serve as a fundamental command used during system rollback (e.g. after a failed or undesirable upgrade).

Comment 3 Mike Snitzer 2013-07-30 16:32:24 UTC

Patches are available here, last rebased to lvm2 2.0.99:

http://people.redhat.com/msnitzer/patches/upstream/thin-snapshot-merge/series.html

(the get_thin_device_id() method needs to be implemented in terms of proper lvm2 code placement)

Comment 4 Fedora End Of Life 2013-09-16 16:40:31 UTC

This bug appears to have been reported against 'rawhide' during the Fedora 20 development cycle.
Changing version to '20'.

More information and reason for this action is here:
https://fedoraproject.org/wiki/BugZappers/HouseKeeping/Fedora20

Comment 5 Zdenek Kabelac 2013-12-05 13:45:27 UTC

Upstream support has been commited - starting with:

https://www.redhat.com/archives/lvm-devel/2013-December/msg00017.html


Usage:

lvconvert --merge  vg/thinsnap

This will merge thinsnap into its origin device - effectively thinsnap replaces origin and origin is deleted. This works only in the case both volumes could be deactivated. If they are i.e. mounted, merge is deferred to the next activation of merged (origin) LV.

While vg/thinsnap is 'merged' and deferred it's not longer accessible for lv commands - so it cannot be deactivated  (only volume for deactivation is  origin), but its still visible via  'lvs -a' as and invisible volume.

For some use-cases see:

https://www.redhat.com/archives/lvm-devel/2013-December/msg00026.html