Telegraf采集端性能优化

该方案来源于 夜莺交流互助群 群友提供，可参考使用

修改telegraf output的方式

• 原先的，官方教程推荐的配置方式如下：

[[outputs.opentsdb]]
  host = "opentsdb_host"
  port = opentsdb_port
  http_batch_size = 50
  http_path = "/opentsdb/put"
  debug = false
  separator = "_"

• 更优的、性能有较大提升的配置方式：

[[outputs.http]]
  url = "http://n9e_ip/prometheus/v1/write"
  data_format = "prometheusremotewrite"
  [outputs.http.headers]
     Content-Type = "application/x-protobuf"
     Content-Encoding = "snappy"
     X-Prometheus-Remote-Write-Version = "0.1.0"