I have many errors like that in log file :

Category: org.ametys.runtime.plugins.core.administrator.jvmstatus.monitoring.RRDsFeederTimerTask
Message: Unable to collect sample for: http-request
Location: org.ametys.runtime.plugins.core.administrator.jvmstatus.monitoring.RRDsFeederTimerTask.run(RRDsFeederTimerTask.java:108)
Thrown:
java.lang.IllegalArgumentException: Datasource processed not found
at org.rrd4j.core.Sample.setValue(Sample.java:67)
at org.ametys.runtime.plugins.core.administrator.jvmstatus.monitoring.sample.HttpRequestSampleManager._internalCollect(HttpRequestSampleManager.java:50)
at org.ametys.runtime.plugins.core.administrator.jvmstatus.monitoring.sample.AbstractSampleManager.collect(AbstractSampleManager.java:186)
at org.ametys.runtime.plugins.core.administrator.jvmstatus.monitoring.RRDsFeederTimerTask.run(RRDsFeederTimerTask.java:104)
at java.util.TimerThread.mainLoop(Timer.java:512)
at java.util.TimerThread.run(Timer.java:462)