Graphite

Gatling offers a way to have some live statistics through Graphite so that you don't have to wait for the generation of the final report to see what happens.

This way, you can also monitor what happens on the client side AND the server side and collect all the data in one central repository.

Configuration of Graphite

In $GRAPHITE_HOME/conf/storage-schemas.conf:

[Gatling stats]
priority = 110
pattern = ^gatling\..*
retentions = 1s:6d,10s:60d

In $GRAPHITE_HOME/conf/storage-aggregation.conf:

[sum]
pattern = \.count$
xFilesFactor = 0
aggregationMethod = sum

[min]
pattern = \.min$
xFilesFactor = 0.1
aggregationMethod = min

[max]
pattern = \.max$
xFilesFactor = 0.1
aggregationMethod = max

[default_average]
pattern = .*
xFilesFactor = 0.3
aggregationMethod = average

Configuration of Gatling

In $GATLING_HOME/conf/gatling.conf, be sure to :

have the GraphiteDataWriter in the list of writers
have the correct host and port for Graphite

data {
  writers = [console, file, graphite]
  reader = file
}
graphite {
  host = "192.168.56.101"
  port = 2003
  bucketWidth = 100
}

Metrics

Two types of metrics are provided by Gatling :

Users metrics
Requests metrics

User metrics

Users metrics give you, for each scenario of your simulation (or all scenarios using allUsers) :

waiting : # of users waiting to start the scenario
active : # of users currently running the scenario
done : # of users who have completed the scenario

The metric path for users metrics is gatling.scenarioName.users.category, where :

scenarioName is the name of your scenario
metric is one of the metrics described above

Request metrics

Requests metrics give you, for each request (or all requests using allRequests) and by status (OK, KO and both) :

count : requests/sec
min and max : Min and Max response time for the request
percentilesXX : First and second percentiles, as defined in gatling.conf (defaults are 95th and 99th percentiles)

The metric path for requests metrics is gatling.scenarioName.requestName.status.metric, where :

scenarioName is the name of your scenario
requestName is the name of your request
status is either ok (for successful requests), ko (for failed requests) or all (for both successful and failed requests)
metric is one of the metrics described above