Bug 732531

Summary: RFE: LVM RAID - Support RAID1 merge of LVs split from array with change tracking
Product: Red Hat Enterprise Linux 6 Reporter: Jonathan Earl Brassow <jbrassow>
Component: lvm2Assignee: Jonathan Earl Brassow <jbrassow>
Status: CLOSED ERRATA QA Contact: Corey Marthaler <cmarthal>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 6.2CC: agk, dwysocha, heinzm, jbrassow, mbroz, prajnoha, prockai, thornber, zkabelac
Target Milestone: rcKeywords: FutureFeature
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: lvm2-2.02.95-1.el6 Doc Type: Enhancement
Doc Text:
New Feature to 6.3. No documentation required. Bug 732458 is the bug that requires a release note for the RAID features. Other documentation is found in the LVM manual. Operational bugs need no documentation because they are being fixed before their initial release.
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-06-20 14:59:43 UTC Type: ---
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: 749672, 756082    

Description Jonathan Earl Brassow 2011-08-22 19:55:01 UTC
LVs that are split from a RAID1 array with '--trackchanges' should be able to be merged back into the array from which they came.  Only those portions of the array which changed since the split should be resync'ed.

Comment 1 Jonathan Earl Brassow 2011-08-22 20:04:41 UTC
Command synopsis:
example~> lvconvert --merge vg/lv_rimage_2

Release criteria (test requirements):
- Merge should be successful
- Image should be resync'ed
- No data corruption (stale data from image should not be accessible regardless of which image was split and then merged)
- There should be /some/ way of detecting when an image has finished its resync (either via dmsetup or some LVM command (e.g. 'lvs'))

Comment 2 Corey Marthaler 2011-08-31 18:42:35 UTC
Adding QA ack for 6.3.

Devel will need to provide unit testing results however before this bug can be
ultimately verified by QA.

Comment 4 Jonathan Earl Brassow 2011-12-01 00:26:33 UTC
Unit test verification:

[root@bp-01 ~]# lvconvert --splitmirrors 1 --trackchanges vg/lv
  lv_rimage_1 split from lv for read-only purposes.
  Use 'lvconvert --merge vg/lv_rimage_1' to merge back into lv
[root@bp-01 ~]# devices vg
  LV            Copy%  Devices                      
  lv            100.00 lv_rimage_0(0),lv_rimage_1(0)
  [lv_rimage_0]        /dev/sdc1(1)                 
  lv_rimage_1          /dev/sdd1(1)                 
  [lv_rmeta_0]         /dev/sdc1(0)                 
  [lv_rmeta_1]         /dev/sdd1(0)                 
[root@bp-01 ~]# lvconvert --merge vg/lv_rimage_1
  vg/lv_rimage_1 successfully merged back into vg/lv
[root@bp-01 ~]# devices vg
  LV            Copy%  Devices                      
  lv            100.00 lv_rimage_0(0),lv_rimage_1(0)
  [lv_rimage_0]        /dev/sdc1(1)                 
  [lv_rimage_1]        /dev/sdd1(1)                 
  [lv_rmeta_0]         /dev/sdc1(0)                 
  [lv_rmeta_1]         /dev/sdd1(0)

Comment 5 Jonathan Earl Brassow 2011-12-01 00:27:24 UTC
Feature present in LVM2 version 2.02.89

Comment 8 Jonathan Earl Brassow 2012-04-23 18:19:25 UTC
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
New Feature to 6.3.  No documentation required.

Bug 732458 is the bug that requires a release note for the RAID features.  Other documentation is found in the LVM manual.

Operational bugs need no documentation because they are being fixed before their initial release.

Comment 9 Corey Marthaler 2012-05-02 23:43:05 UTC
Feature verified in the latest kernel.

2.6.32-269.el6.x86_64
lvm2-2.02.95-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012
lvm2-libs-2.02.95-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012
lvm2-cluster-2.02.95-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012
udev-147-2.41.el6    BUILT: Thu Mar  1 13:01:08 CST 2012
device-mapper-1.02.74-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012
device-mapper-libs-1.02.74-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012
device-mapper-event-1.02.74-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012
device-mapper-event-libs-1.02.74-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012
cmirror-2.02.95-7.el6    BUILT: Wed May  2 05:14:03 CDT 2012

Comment 11 errata-xmlrpc 2012-06-20 14:59:43 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2012-0962.html