Elasticsearch indexing performance below expectations at a single installation

we had a bottleneck once, when we updated this to frequently, directly with a script in the logstash -> elasticsearch pipe ,

thanks to your support we identified it and built a queue based service, since than, this issue was solved.
in the test, that inserts bulk messages directly into elasticsearch, without the logstash pipe, the performance is also bad, so i don't think we've got another issue with updates