Bug 1376212

Summary: lvconvert splits allocation unnecessarily for legacy "mirror" segment type - take 3
Product: Red Hat Enterprise Linux 7 Reporter: Corey Marthaler <cmarthal>
Component: lvm2Assignee: Heinz Mauelshagen <heinzm>
lvm2 sub component: Mirroring and RAID QA Contact: cluster-qe <cluster-qe>
Status: CLOSED WONTFIX Docs Contact:
Severity: low    
Priority: unspecified CC: agk, heinzm, jbrassow, msnitzer, prajnoha, zkabelac
Version: 7.3   
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
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Last Closed: 2020-02-28 21:14:17 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Corey Marthaler 2016-09-14 21:39:05 UTC 
Description of problem:
This is a follow up to the remaining issues in bug 1158172.

Scenario 1 in comment #26 of bug 1158172

### Scenario 1: No tags in lvm.conf, No alloc flags used in convert
[root@host-117 ~]# lvconvert -m1 --type mirror mirror_sanity/span
  Logical volume mirror_sanity/span being converted.
  mirror_sanity/span: Converted: 1.00%
  mirror_sanity/span: Converted: 100.00%

[root@host-117 ~]# lvs -a -o +devices
  LV              VG            Attr       LSize    Log         Cpy%Sync Devices                          
  span            mirror_sanity mwi-a-m--- 400.00m  [span_mlog] 100.00   span_mimage_0(0),span_mimage_1(0)
  [span_mimage_0] mirror_sanity iwi-aom--- 400.00m                       /dev/sdf1(100)                   
  [span_mimage_0] mirror_sanity iwi-aom--- 400.00m                       /dev/sdd2(100)                   
  [span_mimage_1] mirror_sanity iwi-aom--- 400.00m                       /dev/sdd2(149)                   
  [span_mimage_1] mirror_sanity iwi-aom--- 400.00m                       /dev/sdf1(151)                   
  [span_mlog]     mirror_sanity lwi-aom---   4.00m                       /dev/sda1(0)
# This appears wrong as it's not redundant


Other questions remaining for tagged/cling scenarios in comment #26 of bug 1158172:
   - should tagged PVs take precedence over untagged PVs when choosing, even if smaller?
    - should normal allocation take account of PVs used by other segments when selecting parallel space?
      so a new mirror leg should avoid all PVs used by all segments of the LV already thereby avoiding A-B / B-A layouts




Version-Release number of selected component (if applicable):
3.10.0-501.el7.x86_64

lvm2-2.02.165-2.el7    BUILT: Wed Sep 14 09:01:43 CDT 2016
lvm2-libs-2.02.165-2.el7    BUILT: Wed Sep 14 09:01:43 CDT 2016
lvm2-cluster-2.02.165-2.el7    BUILT: Wed Sep 14 09:01:43 CDT 2016
device-mapper-1.02.134-2.el7    BUILT: Wed Sep 14 09:01:43 CDT 2016
device-mapper-libs-1.02.134-2.el7    BUILT: Wed Sep 14 09:01:43 CDT 2016
device-mapper-event-1.02.134-2.el7    BUILT: Wed Sep 14 09:01:43 CDT 2016
device-mapper-event-libs-1.02.134-2.el7    BUILT: Wed Sep 14 09:01:43 CDT 2016
device-mapper-persistent-data-0.6.3-1.el7    BUILT: Fri Jul 22 05:29:13 CDT 2016