Hi, all.
    
     I have a mosquitto server deployed in a Docker container. I mounted
    a volume for logs and persistence file and everythings seems to work
    fine except for the persistence: The mosquitto.db files doesn't
    grows even if I stop any subscriptor which could empty queues.
     Write permissions on db path are fine, if I delete the file
    mosquitto.db, mosquitto creates it again when started. But nothing
    seems to be written into and when mosquitto logs to have written his
    in-memory database to the file, the mosquitto.db was touched and its
    "last time modified" updated accordingly.
     Any suggestion is strongly appreciated.
     
    
    # cat /etc/redhat-release (both container and host)
      CentOS Linux release 7.4.1708 (Core)
    # cat /etc/yum.repos.d/mosquitto.repo
      [home_oojah_mqtt]
        name=mqtt (CentOS_CentOS-7)
        type=rpm-md
baseurl=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-7/
        gpgcheck=1
gpgkey=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-7/repodata/repomd.xml.key
        enabled=1
    mosquitto version 1.4.14 (build date
        2017-09-14 18:40:30+0000)
    
    mosquitto config file:
    
    retry_interval 20
        user mosquitto
        port 1883
        protocol mqtt
        autosave_interval 180
        autosave_on_changes false
        persistence true
        persistence_file mosquitto.db
        persistence_location /var/lib/mosquitto/
        log_dest file /var/log/mosquitto/mosquitto.log
        log_type all
        connection_messages true
        log_timestamp true
        allow_anonymous true
        
      
    From Mosquitto log:
    
    Fri Feb  9 17:50:41 2018: Saving in-memory
        database to /var/lib/mosquitto/mosquitto.db.
    
      
    Mosquitto db file (host side):
    
    -rw------- 1 systemd-bus-proxy
        systemd-bus-proxy 39 Feb  9 17:56
        mosquitto-db/_data/mosquitto.db
    Mosquitto db file (from the container):
    
    # ll /var/lib/mosquitto/mosquitto.db
    -rw------- 1 mosquitto mosquitto 39 Feb  9
        16:56 /var/lib/mosquitto/mosquitto.db
      
      
    
    -- 
Best regards, Matteo Fracassetti.