Since bfsync uses Berkeley DB to store its data, the data integrity is protected even against extreme failures. For instance if the process that accesses the database crashes or is killed, or if everything on the host running bfsync is interrupted due to power failure or kernel panic. After such failures, the database needs recovery. Trying to mount bfsyncfs in that situation or using the bfsync utility will fail.

In this situation running bfsync recover will restore the database to a consistent state and after that, normal work can start again. The repository is choosen either from the <repo> argument, or if that is not there, from the directory bfsync recover was started in.

Recovery can not be done if there are still processes that are using the database. In that case, these processes need to be terminated before recovery. Attempting recovery if it is not necessary is safe, so it won’t change the database state.