在启动elasticsearch时报如下错误，而之前启动的时候是成功的。
Java HotSpot(TM) 64-Bit Server VM warning: INFO: os::commit_memory(0x0000000085330000, 2060255232, 0) failed; error=‘Cannot allocate memory‘ (errno=12)
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 2060255232 bytes for committing reserved memory.
# An error report file with more information is saved as:
# /usr/local/elasticsearch-7.5.1/bin/xxxxxxxx.log
解决方法：在elasticsearch安装包下的config/jvm.options中，修改配置调整Heap size：
-Xms200m
-Xmx200m
然后重启elsaticsearch即可。