Provided by: vnstat_1.18-1_amd64 bug


       vnstatd - daemon based database updating for vnStat


       vnstatd  [  -Ddnpsv?   ]  [  --alwaysadd ] [ --config file ] [ --daemon ] [ --debug ] [ -g
       group ] [ --group group ] [ --help ] [ --noadd ] [ --nodaemon  ]  [  --pidfile  file  ]  [
       --sync ] [ --u user ] [ --user user ] [ --version ]


       The purpose of vnstatd is to provide a more flexible and robust way for updating vnstat(1)
       databases than what using cron  for  updating  can  provide.  The  daemon  makes  possible
       updating  databases more often but at the same time causes less disk access since data can
       be cached and written only later to disk at a user configurable interval. The availability
       of  each  interface is automatically tracked which removes the need for additional scripts
       to be implemented and called when an interface comes online or goes offline.

       vnstatd is the command for starting the daemon. The daemon can either fork itself  to  run
       as  a  background process or stay attached to the terminal.  It supports logging to a user
       selectable file or using syslog.

       Once started, the daemon will read vnstat.conf(5) if available and then check if there are
       any  databases  present  in  the  database  directory  that  has  been  specified  in  the
       configuration file. By default, if no databases are found, new databases will  be  created
       during  startup for all available interfaces excluding pseudo interfaces lo, lo0 and sit0.
       This automatic database addition behaviour can  be  disabled  using  the  --noadd  option.
       Alternatively,  it  is  possible  to  allow  the  daemon  to create new databases whenever
       previously unseen interfaces become visible using the --alwaysadd option.

       The daemon will proceed to track the availability of  monitored  interfaces,  process  the
       interface  traffic  statistics and write new values to databases at a configured interval.
       As a result, the daemon ends up spending most of the time sleeping between updates.


              Enable automatic creation of new databases for previously unseen interfaces even if
              the  database  directory already contains databases when the daemon is started. New
              databases will also get created  for  new  interfaces  seen  while  the  daemon  is
              running. Pseudo interfaces lo, lo0 and sit0 are excluded from getting added.

       --config file
              Use  file  as  configuration file instead of using normal configuration file search

       -d, --daemon
              Fork process to background and run as a daemon.

       -D, --debug
              Provide additional output for debug purposes. The process will stay attached to the
              terminal for output.

       -g, --group group
              Set  daemon process group to group during startup.  group can be either the name of
              the group or a numerical group id. This option can only be used when the process is
              started as root.

              Disable  automatic  creation  of  new databases for all available interfaces if the
              daemon is started with zero database found. Pseudo interfaces lo, lo0 and sit0  are
              excluded from getting added.

       -n, --nodaemon
              Stay in foreground attached to the current terminal and start the update process.

       -p, --pidfile file
              Write the process id to file and use it for locking so that another instance of the
              daemon cannot be started if the same file is specified.

       -s, --sync
              Synchronize internal counters in the  database  with  interface  counters  for  all
              available  interfaces  before  starting traffic monitoring.  Use this option if the
              traffic between the previous shutdown and the current startup of the  daemon  needs
              to  be  ignored.  This  option isn't required in normal use because the daemon will
              automatically synchronize the internal counters after a system  reboot,  if  enough
              time has passed since the daemon was previously running or if the internal counters
              are clearly out of sync.

       -u, --user user
              Set daemon process user to user during startup.  user can be either  the  login  of
              the  user  or a numerical user id. This option can only be used when the process is
              started as root.

       -v, --version
              Show current version of the daemon executable.

       -?, --help
              Show a command option summary.


       The behaviour of  the  daemon  is  configured  mainly  using  the  configuration  keywords
       UpdateInterval, PollInterval and SaveInterval in the configuration file.

       UpdateInterval  defines  in  seconds  how often the interface data is fetched and updated.
       This is similar to the run interval for alternative cron  based  updating.   However,  the
       difference is that the data doesn't directly get written to disk during updates.

       PollInterval  defines in seconds how often the list of available interfaces is checked for
       possible changes. The minimum value is 2 seconds and the maximum 60 seconds.  PollInterval
       also defines the resolution for other intervals.

       SaveInterval  defines  in  minutes  how often cached interface data is written to disk.  A
       write can only occur during the updating of interface data. Therefore, the value should be
       a multiple of UpdateInterval with a maximum value of 60 minutes.

       The  default  values  of  UpdateInterval 30, SaveInterval 5 and PollInterval 5 are usually
       suitable for most systems and provide a similar behaviour as cron based updating does  but
       with a better resolution for interface changes and fast interfaces.

       For  embedded  and/or  low  power systems more tuned configurations are possible.  In such
       cases if the interfaces are mostly static the PollInterval  can  be  increased  to  around
       10-30  seconds  and  UpdateInterval set to 60 seconds. Higher values up to 300 seconds are
       possible if the interface speed is 10 Mbit or less.  SaveInterval  can  be  increased  for
       example to 15, 30 or even 60 minutes depending on how often the data needs to be viewed.


       The  daemon is listening to signals SIGHUP, SIGINT and SIGTERM.  Sending the SIGHUP signal
       to the daemon will cause cached data to be written to  disk,  a  rescan  of  the  database
       directory  and  a  reload  of  settings from the configuration file. However, the pid file
       location will not be changed even if it's configuration setting has been modified.

       SIGTERM and SIGINT signals will cause the daemon to write all cached data to disk and then


              Default database directory. Files are named according to the monitored interfaces.

              Config  file that will be used unless $HOME/.vnstatrc exists. See the configuration
              chapter and vnstat.conf(5) for more information.

              Log file that will be used if logging to file  is  enable  and  no  other  file  is
              specified in the config file.

              File  used  for  storing  the  process  id  if  no  other  file is specified in the
              configuration file or using the command line parameter.


       Updates needs to be executed at least as often as it is  possible  for  the  interface  to
       generate enough traffic to overflow the kernel interface traffic counter. Otherwise, it is
       possible that some traffic won't be seen. This isn't an issue for 64-bit  kernels  but  at
       least  one  update  every  hour is always required in order to provide proper input.  With
       32-bit kernels, the maximum time between two updates depends on how fast the interface can
       transfer 4 GiB. Calculated theoretical times are:

              10 Mbit:        54 minutes
              100 Mbit:        5 minutes
              1000 Mbit:      30 seconds

       However,  for 1000 Mbit interfaces updating once every minute is usually a usable solution
       if faster updates can't be used.

       Virtual and aliased interfaces cannot be monitored  because  the  kernel  doesn't  provide
       traffic information for that type of interfaces. Such interfaces are usually named eth0:0,
       eth0:1, eth0:2 etc. where eth0 is the actual interface being aliased.


       Teemu Toivola <tst at iki dot fi>


       vnstat(1), vnstati(1), vnstat.conf(5), signal(7)