Usage # Real time monitoring modes

In addition to output features using the data store by the daemon to the database, vnStat has two real time monitoring modes which don't have a dependency to the daemon or the database. Both can be even used directly with only the vnstat binary available without anything else installed.

-tr / --traffic

Calculates the traffic for the default or given interfaces for 5 seconds (default, unless otherwise specified) and then shows the result in human readable format.

Supported additional parameters:

• --json - output in json format
• -ru / --rateunit - switch between bytes/s and bits/s, overrides RateUnit from configuration file

Command examples:

• vnstat -tr - default interface selected, 5 seconds monitoring (unless configuration file says otherwise)
• vnstat -tr 5 - default interface selected, 5 seconds monitoring
• vnstat -tr 10 -i eth1 or vnstat -tr 10 eth1 (starting from version 2.8) - 10 seconds monitoring for interface eth1
• vnstat -tr 2 --json - default interface selected, 2 seconds monitoring, json format output

Output examples:

$ vnstat -tr
51 packets sampled in 5 seconds
Traffic average for eth0

      rx           1.74 KB/s             5 packets/s
      tx             793 B/s             4 packets/s

$ vnstat -tr 2 --json
{"jsonversion":"1","vnstatversion":"2.9","interface":"eth0","sampletime":2,"rx":{"ratestring":"4.57 KB/s","bytespersecond":4679,"packetspersecond":20,"bytes":9359,"packets":41},"tx":{"ratestring":"3.67 KB/s","bytespersecond":3757,"packetspersecond":18,"bytes":7515,"packets":36}}

-l / --live

Displays current transfer rate for the selected interface in real time until interrupted. Statistics will be shown after interruption if the runtime was more than 10 seconds. An optional mode parameter can be used to select between the displaying of packets per second (mode 0) and transfer counters (mode 1) during execution.

Supported additional parameters:

• --json - output in json format
• --style 4 - output a new line every 2 seconds instead of reusing one line
• -ru / --rateunit - switch between bytes/s and bits/s, overrides RateUnit from configuration file

Command examples:

• vnstat -l - default interface selected, default human readable output
• vnstat -l -i eth1 or vnstat -l eth1 (starting from version 2.8) - default human readable output for interface eth1
• vnstat -l --help - help output for optional mode parameter
• vnstat -l 0 - default interface selected, default human readable output with packets per seconds shown
• vnstat -l 1 - default interface selected, default human readable output with transfer sum shown
• vnstat -l --json - default interface selected, json format output with new line every two seconds

Output examples:

$ vnstat -l
Monitoring eth0...    (press CTRL-C to stop)

   rx:       2.57 KB/s     8 p/s          tx:         693 B/s     6 p/s


 eth0  /  traffic statistics

                           rx         |       tx
--------------------------------------+------------------
  bytes                     15.25 MB  |       483.56 KB
--------------------------------------+------------------
          max              1.81 MB/s  |      66.12 KB/s
      average            300.40 KB/s  |       9.30 KB/s
          min                884 B/s  |          35 B/s
--------------------------------------+------------------
  packets                      12223  |            4131
--------------------------------------+------------------
          max               1382 p/s  |         408 p/s
      average                235 p/s  |          79 p/s
          min                  3 p/s  |           0 p/s
--------------------------------------+------------------
  time                    52 seconds

$ vnstat -l --json
{"jsonversion":"1","vnstatversion":"2.8","interface":"eth0","sampletime":2}
{"index":1,"seconds":2,"rx":{"ratestring":"56.71 KB/s","bytespersecond":58067,"packetspersecond":48,"bytes":116134,"packets":96,"totalbytes":116134,"totalpackets":96},"tx":{"ratestring":"3.20 KB/s","bytespersecond":3278,"packetspersecond":14,"bytes":6556,"packets":28,"totalbytes":6556,"totalpackets":28}}
{"index":2,"seconds":4,"rx":{"ratestring":"867.84 KB/s","bytespersecond":888671,"packetspersecond":640,"bytes":1777343,"packets":1281,"totalbytes":1893477,"totalpackets":1377},"tx":{"ratestring":"20.69 KB/s","bytespersecond":21188,"packetspersecond":252,"bytes":42376,"packets":505,"totalbytes":48932,"totalpackets":533}}
{"index":3,"seconds":6,"rx":{"ratestring":"2.03 KB/s","bytespersecond":2081,"packetspersecond":10,"bytes":4163,"packets":20,"totalbytes":1897640,"totalpackets":1397},"tx":{"ratestring":"653 B/s","bytespersecond":653,"packetspersecond":6,"bytes":1306,"packets":12,"totalbytes":50238,"totalpackets":545}}
{"index":4,"seconds":8,"rx":{"ratestring":"177.69 KB/s","bytespersecond":181953,"packetspersecond":136,"bytes":363906,"packets":272,"totalbytes":2261546,"totalpackets":1669},"tx":{"ratestring":"2.74 KB/s","bytespersecond":2810,"packetspersecond":26,"bytes":5620,"packets":52,"totalbytes":55858,"totalpackets":597}}
{"index":5,"seconds":10,"rx":{"ratestring":"815.37 KB/s","bytespersecond":834941,"packetspersecond":607,"bytes":1669883,"packets":1214,"totalbytes":3931429,"totalpackets":2883},"tx":{"ratestring":"18.80 KB/s","bytespersecond":19254,"packetspersecond":216,"bytes":38508,"packets":432,"totalbytes":94366,"totalpackets":1029}}
{"seconds":10,"rx":{"maxratestring":"867.84 KB/s","averageratestring":"383.93 KB/s","minratestring":"2.03 KB/s","totalbytes":3931429,"maxbytes":1777343,"minbytes":4163,"totalpackets":2883,"maxpackets":1281,"minpackets":20},"tx":{"maxratestring":"20.69 KB/s","averageratestring":"9.21 KB/s","minratestring":"653 B/s","totalbytes":94366,"maxbytes":42376,"minbytes":1306,"totalpackets":1029,"maxpackets":505,"minpackets":12}}