No host was tried because nodes were unresponsive and the driver marked them as down. When too many nodes get marked as down, the driver eventually runs out of nodes so ends up in NoHostAvailableException.
Nodes become unresponsive because they are overloaded. You either throttle back the app throughput or increase the capacity of your cluster. Cheers! On Thu, Aug 31, 2017 at 1:10 AM, Ivan Iliev <ivan.iliev.il...@gmail.com> wrote: > Hello everyone, > > We are using Cassandra 3.9 for storing quite a lot of data produced from > our tester machines. > > Occasionally, we are seeing issues with apps not being able to communicate > with Cassandra nodes, returning the following errors (captured in > servicemix logs): > >> by: com.datastax.driver.core.exceptions.NoHostAvailableException: All >> host(s) tried for query failed (no host was tried) >> at com.datastax.driver.core.RequestHandler.reportNoMoreHosts( >> RequestHandler.java:218) >> at com.datastax.driver.core.RequestHandler.access$1000( >> RequestHandler.java:43) >> at com.datastax.driver.core.RequestHandler$SpeculativeExecution. >> sendRequest(RequestHandler.java:284) >> at com.datastax.driver.core.RequestHandler.startNewExecution( >> RequestHandler.java:115) >> at com.datastax.driver.core.RequestHandler.sendRequest( >> RequestHandler.java:91) >> at com.datastax.driver.core.SessionManager.executeAsync( >> SessionManager.java:132) >> ... 107 more > > > As a result, apps that try to send data to cassandra get crashed due to > running out of memory and we have to restart the containers in which they > run. > > So far I have not been able to identify what might be the cause for this > as nothing (at least I could not find anything relevant on the timestamps) > in the cassandra debug and system logs. > > Could you share some insight on this ? What to check and where to start > from , in order to troubleshoot this. > > Thanks ! > Ivan >
