Suricata

Currently for both git and 1.4.1 in the suricata.yaml we have:

  # Stats.log contains data from various counters of the suricata engine.
  # The interval field (in seconds) tells after how long output will be written
  # on the log file.
  - stats:
      enabled: yes
      filename: stats.log
      interval: 8

So if you run Suricata like this , even on little traffic, it can inflate the stats.log to a size of few GBs for a few days run.
The more cores you have - the bigger the stats.log in general.

One can add

interval: 8
append: no

Then the stats.log will be cleared/reset every time Suricata is restarted/run.
The option however is not present in the yaml file itself.