Alex, Thanks for your continued research into this.
The upstream 168 changelog is informative (edited for relevant parts): Summary of changes from v167 to v168 ============================================ Kay Sievers (35): udevadm: info --cleanup-db "db_persist=" -> "db_persist" require explicit "db_persist" to exclude device info from --db-cleanup It is somewaht opaque, but the relevant commits appear to be in the current systemd git[1]. Does this mean that dm mapper should set db_persist in the initramfs? Mark [1] https://github.com/search?q=repo%3Asystemd%2Fsystemd+db_persist&type=commits