我收到多个警告：

WARN : Max open files on localhost is 1024, recommend 32768

我不确定这是怎么回事。

/usr/local/accumulo$ ./bin/start-all.sh &
[1] 27142
/usr/local/accumulo$ Starting monitor on localhost
WARN : Max open files on localhost is 1024, recommend 32768
Starting tablet servers .... done
Starting tserver on localhost
WARN : Max open files on localhost is 1024, recommend 32768
2016-12-01 15:14:49,820 [fs.VolumeManagerImpl] WARN : dfs.datanode.synconclose set to false in hdfs-site.xml: data loss is possible on   hard system reset or power loss
2016-12-01 15:14:49,838 [server.Accumulo] INFO : Attempting to talk to zookeeper
2016-12-01 15:14:50,017 [server.Accumulo] INFO : ZooKeeper connected and initialized, attempting to talk to HDFS
2016-12-01 15:14:50,184 [server.Accumulo] INFO : Connected to HDFS
Starting master on localhost
WARN : Max open files on localhost is 1024, recommend 32768
Starting gc on localhost
WARN : Max open files on localhost is 1024, recommend 32768
Starting tracer on localhost
WARN : Max open files on localhost is 1024, recommend 32768

我得到另一个警告，我明白。但是关于max open文件的那个对我来说很奇怪。
如何解决这些警告？
顺便说一下，accumulo正在运行。
以下是有关我的设置的详细信息：
没有可用的lsb模块。分发服务器id:ubuntu描述：ubuntu 16.04.1 lts版本：16.04代号：xenial
8gb内存。仅使用2.3gb（与accumulo一起使用）。