Introduction
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Sometimes you need to run multiple ntopng instances on the same host because
- you want to keep data split on each instance
- for debugging purposes you need to run the ntopng service and start another ntopng from a shell for analyzing a pcap file

In order to run multiple instances you need to make sure they don't share any data directory and redis.

Suppose that you are running an ntopng instance via systemd, and that you want to analyze debug.pcap file. In order
to run this second instance you need to set
- use a different HTTP(S) port other than the one used by the other instance (usually port 3000) (-w for HTTP, and -W for HTTPS)
- use a dfferent redis partition (-r command line option)
- use a unique data directory (-d command line option)

Example:
ntopng -w 3001 -d /tmp/data/ -r @2 -i debug.pcap


Caveats
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1. If you use RRD the -d directory will be enough to keep your data private. If you use InfluxDB make sure
   to use a unique database name to avoid mixing up data. You can set the Influx DB name from inside ntopng
   using the menu Settings -> Timeseries -> InfluxDB Database.

   Note that you need to set this unique database name if you use the second ntopng instance for permanently
   montor traffic, as this is not necessary when analysing a pcap file as timeseries are not written.

2. Each ntopng instance will have a separate user name, password etc. as if they were different instances,