How make logstash run faster?

now I had a problem with logstash, for my clients,I use logstash for bind dns's log collecting,but some clients part of date the ES server can't collectd, I think it's because the logstash can't handle these so many and faster data, the clients which had problem ,they QPS is 1.5 million/min, anyone can help me pls?

Do you have any idea of what your current bottleneck is? CPU? I/O? We need more details about your architecture and your machine specs.