Description of problem: When detaching block SD, SD has to be in maintenance mode. In maintenance mode, SD is disconnected from storage server and LVM VG is deactivated on the host. During detach, engine connects hosts to iscsi storage again, which results in VG activation on the hosts. During detach it disconnects from the storage server, but without deactivating VG. As a result, there are stale DM links on the hosts. This doesn't happen on host which manages SD, but on all other hosts. How reproducible: Always Steps to Reproduce: 1. create iSCSI storage domain 2. put it into maintenance 3. detach SD from the cluster Actual results: Stale DM links on the host. Expected results: No stale DM links on the host. Additional info: Engine connect the hosts in DetachStorageDomainFromPoolCommand.detachStorageDomain() -> connectHostsInUpToDomainStorageServer() https://github.com/oVirt/ovirt-engine/blob/master/backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/storage/domain/DetachStorageDomainFromPoolCommand.java#L101
It turned out that the root cause if bug in LVM: BZ #1932761 Keeping this bug open as can be used to mitigate this issue until is fixed and gets into the RHEL.
Closing, this is not real bug, but was a combination of misconfigured host (missing LVM filter) and LVM bug described in BZ #1932761