low disk watermark [85%] exceeded on

查看elasticsearch的log有报错
tail -f /var/log/elasticsearch/elasticsearch.log

2020-04-15T18:18:38,801][INFO ][o.e.c.r.a.DiskThresholdMonitor] [bvo4zCK] low disk watermark [85%] exceeded on [bvo4zCKHTnyKHNLJzSfg9A][bvo4zCK][/var/lib/elasticsearch/nodes/0] free: 5.5gb[14.2%], replicas will not be assigned to this node

节点上的磁盘空间使用率超过了85%，将不会在该节点上分配副本了

配置文件
/etc/elasticsearch/elasticsearch.yml
中添加如下参数即可(不检测)
cluster.routing.allocation.disk.threshold_enabled: false

或者清空文件/扩大磁盘