Recording & Storage
Recording in Crumb is a straight copy from the camera to disk, no re-encoding, and every recorded segment is indexed in Postgres, which is the single source of truth for what footage exists and where it lives. A recording's file on disk without a matching database row is treated as an orphan and either adopted or cleaned up; a database row pointing at a missing file is treated as dangling and removed. Neither state is allowed to persist silently.
The two recording modes
Continuous records every frame to disk the whole time a camera is active, the well-understood default, and the safe choice while you're still getting a feel for a camera's scene.
Motion is different from what that name implies in most consumer NVRs. Cameras in Motion mode buffer in a RAM cache and only persist to disk when motion is actually detected, pre-roll, the event itself, and post-roll; idle time between events is never written to disk at all. See Recording modes for the full mechanism and its safety rails.
Policies, groups, and storage
Retention is governed by named policies (how much to keep, for how long, across which storage tiers), which can be applied per camera or per camera group so a whole group inherits the same settings at once. See Policies and groups and Storage tiers.
Protecting specific footage
A bookmark can be marked protected, which exempts it from every automatic deletion path, retention sweeps, size caps, and the absolute retention cap alike, until you unpin it. See Bookmarks.