Cluster Shared LVM Limitation
This document (000019652) is provided subject to the disclaimer at the end of this document.
Environment
SUSE Linux Enterprise High Availability Extension 12 SP4
SUSE Linux Enterprise High Availability Extension 12 SP5
SUSE Linux Enterprise Server 15 SP1
SUSE Linux Enterprise Server 12 SP4
SUSE Linux Enterprise Server 12 SP5
Situation
lvcreate -L 1G -s -n test_snap /dev/clustervg/lnx_node1.vda.raw lnx_node1.vda.raw must be active exclusively to create snapshot
SLES15 --> lvmlockd: Trying to create a snapshot on a LVM shared volume will fail to get a lock.
lvcreate --size 200M --snapshot --name snap_shared vg-shared/lv-shared LV locked by other host: vg-shared/lv-shared Failed to lock origin LV vg-shared/lv-shared
Is it possible to resize Shared Logical Volume?
lvextend -r -L +8M /dev/vgshared/lvshared LV is already locked with incompatible mode: vgshared/lvshared
Resolution
Cause
- LVM snapshot feature has never been supported by clvm or lvmlockd from the beginning.
- Resizing Shared Logical Volume Is not supported/possible.
Additional Information
LV activation sy The command activates the LV in shared mode, allowing multiple hosts to activate the LV concurrently. Before activating the LV, the command uses lvmlockd to acquire a shared lock on the LV. If the lock cannot be acquired, the LV is not activated and an error is reported. This would happen if the LV is active exclusively on another host. If the LV type prohibits shared access, such as a snapshot, the command will report an error and fail. The shared mode is intended for a multi-host/cluster application or file system. LV types that cannot be used concurrently from multiple hosts include thin, cache, raid, and snapshot. [...] limitations of shared VGs Things that do not yet work in shared VGs: · using external origins for thin LVs · splitting snapshots from LVs · splitting mirrors in sanlock VGs · pvmove of entire PVs, or under LVs activated with shared locks · vgsplit and vgmerge (convert to a local VG to do this)Note: Resizing Shared LVM should be possible starting from lvm2 v2.03.x in SLE15SP2.
Disclaimer
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- Document ID:000019652
- Creation Date: 22-Jun-2020
- Modified Date:15-Jul-2020
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- SUSE Linux Enterprise High Availability Extension
- SUSE Linux Enterprise Server
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