Bug 1881955

Summary:	VDO target driver should support online rename of its physical device
Product:	[Community] LVM and device-mapper	Reporter:	Zdenek Kabelac <zkabelac>
Component:	lvm2	Assignee:	bjohnsto
lvm2 sub component:	Other	QA Contact:	cluster-qe <cluster-qe>
Status:	CLOSED DUPLICATE	Docs Contact:
Severity:	unspecified
Priority:	unspecified	CC:	agk, bjohnsto, heinzm, jbrassow, msnitzer, pasik, prajnoha, zkabelac
Version:	unspecified	Flags:	pm-rhel: lvm-technical-solution? pm-rhel: lvm-test-coverage?
Target Milestone:	---
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OS:	Unspecified
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Last Closed:	2021-04-30 21:11:05 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:
Bug Depends On:	1888419
Bug Blocks:	1683950

Description Zdenek Kabelac 2020-09-23 13:27:22 UTC

lvm2 currently cannot support the online lvrename with VDOPOOL type volumes.

The reason seems to be VDO's target DM table line uses the name of the device
as one of its parameters on table line.

For this reason lvm2 currently disabled online lvrename with this upstream patch:
https://www.redhat.com/archives/lvm-devel/2020-September/msg00143.html

If this patch is reverted the online lvrename causes this kernel errors:

kvdo102:lvm: Existing layer named vpool1 already uses device /dev/dm-1
kvdo102:lvm: Could not create kernel physical layer. (VDO error 2053, message Cannot share storage device with already-running VDO)
kvdo102:lvm: mapToSystemError: mapping internal status code 2053 (kvdo: VDO_BAD_CONFIGURATION: kvdo: Bad configuration option) to EIO
device-mapper: table: 253:2: vdo: Cannot share storage device with already-running VDO
device-mapper: ioctl: error adding target to table


kernel: 5.9.0-0.rc5.20200916gitfc4f28bb3daf.12.fc34.x86_64
kmod-kvdo-6.2.3.114-2.fc34.x86_64

Comment 1 Zdenek Kabelac 2020-09-23 17:20:31 UTC

Updates:

lvm2 could eventually pass a 'stable' name isntead of  LV name that can be renamed - it could be
i.e.  "#major:#minor"  "dm-#minor" or  "UUID"  (these cannot be changed while device is active/online)
but than tools like  'vdostats' stops working:

i.e.:

# vdostats 
Error sampling device /dev/mapper/vg-vpool1-vpool: [Errno 2] No such file or directory: '/proc/vdo/vg-vpool1-vpool/dedupe_stats'

so the /proc/vdo isn't populate with expected names for these tools
(unclear if there are more users)

Of course the change on lvm2 side would brough some non-trivial complexity when the user would already have 
tables with 'old-way' lines and we would try to use 'new style'

Advantage would be that such change would not need 'kernel' change.

Comment 2 bjohnsto 2021-04-30 21:11:05 UTC


*** This bug has been marked as a duplicate of bug 1888419 ***