Bug 1400021

Summary:	failed to create mirror logical volume by lvcreate on RHEL7.x
Product:	Red Hat Enterprise Linux 7	Reporter:	Zhang Xiaotian <xiaotzha>
Component:	lvm2	Assignee:	LVM and device-mapper development team <lvm-team>
lvm2 sub component:	Clustered Mirror / cmirrord	QA Contact:	cluster-qe <cluster-qe>
Status:	CLOSED NOTABUG	Docs Contact:
Severity:	high
Priority:	high	CC:	agk, guazhang, heinzm, jbrassow, msnitzer, prajnoha, prockai, xiaotzha, yizhan, zkabelac
Version:	7.3
Target Milestone:	rc
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-12-01 11:19:37 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:

Comment 2 Zdenek Kabelac 2016-11-30 10:15:23 UTC

It's rather unfortunate error message.

Mirrored mirror log is ONLY supported with the old DM mirror target.

With new 'raid1' mirroring (kernel code shared with mdraid) - logs are handled differently - every leg has its own log device (typically on the same device as the leg itself).

So there is no need to mirror the log in this case. 

The message just likely needs to emphasize  '--type mirror'  in the message.

But these days you get automatically a better --type raid1 mirror.

If you wish to change back to the old mirror type 'mirror' - please change lvm.conf setting  mirror_segtype_default="mirror"  or just use:

lvcreate --type mirror --mirrors 1.....

There is no plan to support mirroring of new 'raid1' log device.

Comment 4 Zdenek Kabelac 2016-12-01 09:13:43 UTC

There is already a whole new man page:  'man lvmraid'  describing features and usage of new 'mirroring/raid' system used by lvm2.

Original lvcreate man page quite explicitly mentions legacy "mirror" segment type with --mirrorlog option.

So what other changes do you propose here ?