数据量大了以后每隔几天数据就无法正常打到elasticsearch

elk新人，公司一个业务日志数据量在每天200到300G左右，elasticsearch采用三个节点的形式，服务器8核16G，分给elasticsearch的内存为8G，服务均正常，但是正常下来没几天后，数据就无法通过logstash再打到elasticsearch，查看logstash启动日志发现报错说
message=>"Attempted to send a bulk request to Elasticsearch configured at '[\"http://*.*.*.*:*\"]', but an error occurred and it failed! Are you sure you can reach elasticsearch from this machine using the configuration provided?", :error_message=>"*.*.*.*:* failed to respond", :error_class=>"Manticore::ClientProtocolException"
查看elasticsearch日志却无明显报错，将es集群和logstash重启后又能正常。请问这是什么问题导致的呢？