Bug 1985112

Summary:	Scrubbing not possible on RAID5 with 3 LUKS SSDs
Product:	[Community] LVM and device-mapper	Reporter:	nc-duenkekl3
Component:	lvm2	Assignee:	Heinz Mauelshagen <heinzm>
lvm2 sub component:	Mirroring and RAID	QA Contact:	cluster-qe <cluster-qe>
Status:	NEW ---	Docs Contact:
Severity:	medium
Priority:	unspecified	CC:	agk, dkeefe, heinzm, jbrassow, msnitzer, prajnoha, xni, zkabelac
Version:	unspecified	Flags:	pm-rhel: lvm-technical-solution? pm-rhel: lvm-test-coverage?
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Hardware:	x86_64
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description nc-duenkekl3 2021-07-22 22:12:26 UTC

Description of problem:
I can't scrub (check / repair) the raid.

Version-Release number of selected component (if applicable):
LVM2 2.03.12

How reproducible:
Every time.

Steps to Reproduce:
1. Create a LUKS fulldisk partition on each of the 3 SSDs
2. Use LVM to create a RAID 5
3. Format the new RAID5 partition with BTRFS
4. Execute sudo lvchange --syncaction check cryptdata_raid5/home

Actual results:
Command on LV cryptdata_raid5/home does not accept LV type linear.
Command not permitted on LV cryptdata_raid5/home.


Expected results:
Checking and repairing.

Additional info:
Do I need to use MDADM to make a RAID5 first and use the MDADM tools for scrubbing?
The arch wiki said it's perfectly fine to create a RAID5 via LVM directly.

Comment 1 Heinz Mauelshagen 2021-11-03 12:45:53 UTC

Would be valuable to confirm, that an MD array vs. the LVM RAID5 LV behaves differently relative to scrubbing but LVM should actually allow scrubbing on the RaidLV.  I.e. the stack 3x LUKS -> MD RAID5 array -> BTRFS allows for scrubbing.