 <p>I've seen such behavior before, it is probably tomcat and not ec2. Check the following:</p> <p>1- Your threading configuration (maxThreads and acceptCount). I've seen this behavior using the blocking connector when currentThreadsBusy > maxThreads. Check that you have enough threads or use the non-blocking (nio) connector.</p> <p>2- Check that your connection pool can reconnect lost connections automatically (autoReconnect=true in the jdbc url), your threads might be waiting db io on lost connections.</p> <p>Anyway, your ec2 instance is probably still working...</p>