Bug 1881955 - VDO target driver should support online rename of its physical device
Summary: VDO target driver should support online rename of its physical device
Keywords:
Status: CLOSED DUPLICATE of bug 1888419
Alias: None
Product: LVM and device-mapper
Classification: Community
Component: lvm2
Version: unspecified
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
: ---
Assignee: bjohnsto
QA Contact: cluster-qe@redhat.com
URL:
Whiteboard:
Depends On: 1888419
Blocks: 1683950
TreeView+ depends on / blocked
 
Reported: 2020-09-23 13:27 UTC by Zdenek Kabelac
Modified: 2021-04-30 21:11 UTC (History)
8 users (show)

Fixed In Version:
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Environment:
Last Closed: 2021-04-30 21:11:05 UTC
Embargoed:
pm-rhel: lvm-technical-solution?
pm-rhel: lvm-test-coverage?


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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 ***


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