1VNSTATD(8)                       User Manuals                       VNSTATD(8)
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NAME

6       vnstatd - daemon based database updating for vnStat
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SYNOPSIS

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

16       The  purpose  of  vnstatd  is  to provide a flexible and robust way for
17       updating the database that vnstat(1) uses.  The  availability  of  each
18       interface  is  automatically  tracked  which removes the need for addi‐
19       tional scripts to be implemented and called  when  an  interface  comes
20       online or goes offline.
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22       vnstatd  is  the command for starting the daemon. The daemon can either
23       fork itself to run as a background process or stay attached to the ter‐
24       minal.  It supports logging to a user selectable file or using syslog.
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26       Once started, the daemon will read vnstat.conf(5) if available and then
27       check if there is a database present in the database directory that has
28       been specified in the configuration file. By default, if no database is
29       found, a database will be created during startup with entries  for  all
30       available interfaces excluding pseudo interfaces lo, lo0 and sit0. This
31       automatic database entry creation behaviour can be disabled  using  the
32       --noadd  option.  Alternatively,  it is possible to allow the daemon to
33       create new  database  entries  whenever  previously  unseen  interfaces
34       become visible using the --alwaysadd option.
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36       The  daemon  will proceed to track the availability of monitored inter‐
37       faces, process the interface traffic statistics and write new values to
38       the  database at a configured interval. As a result, the daemon ends up
39       spending most of the time sleeping between updates.
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OPTIONS

43       --alwaysadd
44              Enable automatic creation of new database entries for previously
45              unseen  interfaces  even  if the database directory already con‐
46              tains a database  when  the  daemon  is  started.  New  database
47              entries  will also get created for new interfaces seen while the
48              daemon is running.  Pseudo  interfaces  lo,  lo0  and  sit0  are
49              excluded from getting added.
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52       --config file
53              Use  file  as configuration file instead of using automatic con‐
54              figuration file search functionality.
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57       -d, --daemon
58              Fork process to background and run as a daemon.
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61       -D, --debug
62              Provide additional output for debug purposes. The  process  will
63              stay attached to the terminal for output.
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66       -g, --group group
67              Set  daemon process group to group during startup.  group can be
68              either the name of the group  or  a  numerical  group  id.  This
69              option can only be used when the process is started as root.
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72       --noadd
73              Disable  automatic  creation  of  new  database  entries for all
74              available interfaces if the daemon is started with  no  database
75              found. Pseudo interfaces lo, lo0 and sit0 are excluded from get‐
76              ting added.
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79       -n, --nodaemon
80              Stay in foreground attached to the current  terminal  and  start
81              the update process.
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84       -p, --pidfile file
85              Write  the  process  id  to  file and use it for locking so that
86              another instance of the daemon cannot be  started  if  the  same
87              file is specified.
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90       -s, --sync
91              Synchronize  internal  counters  in  the database with interface
92              counters for all available interfaces  before  starting  traffic
93              monitoring.  Use this option if the traffic between the previous
94              shutdown and the current startup  of  the  daemon  needs  to  be
95              ignored.  This  option  isn't required in normal use because the
96              daemon will  automatically  synchronize  the  internal  counters
97              after  a system reboot, if enough time has passed since the dae‐
98              mon was previously running  or  if  the  internal  counters  are
99              clearly out of sync.
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102       -u, --user user
103              Set  daemon  process  user  to user during startup.  user can be
104              either the login of the user or a numerical user id. This option
105              can only be used when the process is started as root.
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108       -v, --version
109              Show current version of the daemon executable.
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112       -?, --help
113              Show a command option summary.
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CONFIGURATION

117       The  behaviour  of the daemon is configured mainly using the configura‐
118       tion keywords UpdateInterval, PollInterval and SaveInterval in the con‐
119       figuration file.
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122       UpdateInterval  defines  in  seconds  how  often  the interface data is
123       fetched and updated.  This is similar to the run interval for  alterna‐
124       tive  cron  based  updating.   However, the difference is that the data
125       doesn't directly get written to disk during updates.
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128       PollInterval defines in seconds how often the list of available  inter‐
129       faces  is  checked for possible changes. The minimum value is 2 seconds
130       and the maximum 60 seconds.  PollInterval also defines  the  resolution
131       for other intervals.
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134       SaveInterval  defines  in  minutes  how  often cached interface data is
135       written to disk.  A write can only occur during the updating of  inter‐
136       face  data. Therefore, the value should be a multiple of UpdateInterval
137       with a maximum value of 60 minutes.
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140       The default values of UpdateInterval 30, SaveInterval 5 and  PollInter‐
141       val  5  are usually suitable for most systems and provide a similar be‐
142       haviour as cron based updating does but with a  better  resolution  for
143       interface changes and fast interfaces.
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146       For  embedded  and/or  low  power systems more tuned configurations are
147       possible.  In such cases  if  the  interfaces  are  mostly  static  the
148       PollInterval  can be increased to around 10-30 seconds and UpdateInter‐
149       val set to 60 seconds. Higher values up to 300 seconds are possible  if
150       the  interface speed is 10 Mbit or less.  SaveInterval can be increased
151       for example to 15, 30 or even 60 minutes depending  on  how  often  the
152       data needs to be viewed.
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SIGNALS

156       The daemon is listening to signals SIGHUP, SIGINT and SIGTERM.  Sending
157       the SIGHUP signal to the daemon will cause cached data to be written to
158       disk,  a rescan of the database directory and a reload of settings from
159       the configuration file. However, the pid  file  location  will  not  be
160       changed even if it's configuration setting has been modified.
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163       SIGTERM  and  SIGINT  signals will cause the daemon to write all cached
164       data to disk and then exit.
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FILES

168       /var/lib/vnstat/
169              Default database directory.
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172       /etc/vnstat.conf
173              Config file that will be used unless $HOME/.vnstatrc exists. See
174              the  configuration  chapter and vnstat.conf(5) for more informa‐
175              tion.
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178       /var/log/vnstat.log
179              Log file that will be used if logging to file is enable  and  no
180              other file is specified in the config file.
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183       /var/run/vnstat.pid
184              File  used for storing the process id if no other file is speci‐
185              fied in the configuration file or using the command line parame‐
186              ter.
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RESTRICTIONS

190       Updates need to be executed at least as often as it is possible for the
191       interface to generate enough traffic to overflow the  kernel  interface
192       traffic  counter.  Otherwise, it is possible that some traffic won't be
193       seen. With 32-bit kernels, the maximum time between two updates depends
194       on  how  fast  the interface can transfer 4 GiB. Calculated theoretical
195       times are:
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197              10 Mbit:        54 minutes
198              100 Mbit:        5 minutes
199              1000 Mbit:      30 seconds
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201       However, for 1000 Mbit interfaces updating once every minute is usually
202       a usable solution if a shorter update interval can't be used.
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204       Virtual  and  aliased interfaces cannot be monitored because the kernel
205       doesn't provide traffic information for that type of  interfaces.  Such
206       interfaces  are usually named eth0:0, eth0:1, eth0:2 etc. where eth0 is
207       the actual interface being aliased.
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AUTHOR

211       Teemu Toivola <tst at iki dot fi>
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SEE ALSO

215       vnstat(1), vnstati(1), vnstat.conf(5), signal(7)
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219version 2.6                      JANUARY 2020                       VNSTATD(8)
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