Bug 1925530

Summary:	Cannot recreate volume group when using Raid on LVM
Product:	Red Hat Enterprise Linux 7	Reporter:	Renaud Métrich <rmetrich>
Component:	rear	Assignee:	Pavel Cahyna <pcahyna>
Status:	CLOSED MIGRATED	QA Contact:	CS System Management SST QE <rhel-cs-system-management-subsystem-qe>
Severity:	high	Docs Contact:
Priority:	high
Version:	7.9	CC:	ovasik, pcahyna
Target Milestone:	rc	Keywords:	MigratedToJIRA
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Hardware:	All
OS:	Linux
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Last Closed:	2023-09-22 00:08:59 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Renaud Métrich 2021-02-05 13:07:42 UTC

Description of problem:

See Upstream PR https://github.com/rear/rear/pull/2564

When having a LV in Raid, and 2 PVs making the VG, an error occurs when re-creating the VG in case Migration mode is used, which usually is the default since having multiple disks with same size make ReaR do a mapping and enter Migration mode.

-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
Start system layout restoration.
Disk '/dev/vda': creating 'msdos' partition table
Disk '/dev/vda': creating partition number 1 with name 'primary'
Disk '/dev/vda': creating partition number 2 with name 'primary'
Creating LVM PV /dev/vdb
Creating LVM PV /dev/vdc
Creating LVM PV /dev/vda2
Creating LVM VG 'data'; Warning: some properties may not be preserved...
The disk layout recreation script failed
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Internally the failure happens because a "vgcreate" is used on the existing VG, no "vgremove" is ever performed.

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

All versions, including Upstream

How reproducible:

Always

Steps to Reproduce:

1. Install a system

2. Add 2 additional disks that will be used to host a LVM VG with *same* size

/dev/vdb
/dev/vdc

3. Create a Raid volume

# pvcreate /dev/vdb
# pvcreate /dev/vdc
# vgcreate data /dev/vdb /dev/vdc
# lvcreate -n vol1 -L 1G -m 1 data
# mkfs.xfs /dev/data/vol1
# mount /dev/data/vol1 /mnt

4. Build a rescue image and perform a recovery

Actual results:

Failure

Expected results:

No failure

Additional info:

There is no easy workaround, the admin needs to edit the diskrestore.sh file.

Comment 2 Pavel Cahyna 2021-02-05 13:41:37 UTC

Does the problem occur only when restoring to disks that have existing data? If so, wouldn't it help to wipe the disks first before restoring to them?

Comment 3 Renaud Métrich 2021-02-05 14:21:01 UTC

Yes, only upon recovering an existing system.
Wiping works but requires manual intervention.

Comment 4 Pavel Cahyna 2021-02-05 15:05:20 UTC

This sounds like the case in bz1919989, which did not involve RAID. So I think the problem is not restricted to RAID.

Comment 5 Renaud Métrich 2021-02-05 15:31:43 UTC

Very likely indeed, I think this happens as soon as a volume group has multiple PVs on different disks.
What is really required is to have ReaR enter Migration mode. There is no issue with the `vgcfgrestore` way.

Comment 7 RHEL Program Management 2023-09-21 23:35:29 UTC

Issue migration from Bugzilla to Jira is in process at this time. This will be the last message in Jira copied from the Bugzilla bug.

Comment 8 RHEL Program Management 2023-09-22 00:08:59 UTC

This BZ has been automatically migrated to the issues.redhat.com Red Hat Issue Tracker. All future work related to this report will be managed there.

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