1.hadoop checknative 出现如下报错
openssl: false Cannot load libcrypto.so (libcrypto.so: cannot open shared object file: No such file or directory)!
对于redhat7.2来说，执行如下：
sudo ln -s /usr/lib64/libcrypto.so.1.0.2k /usr/lib64/libcrypto.so
2.将dfs.data.dir->配置成[SSD]file:///mnt/ssd01/dfs/data，即配置为SSD存储策略后，无法put文件，出错如下：
put: File /input/word._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1). There are 9 datanode(s) running and no node(s) are excluded in this operation.
解决办法：设置存储策略为ALL_SSD
hdfs storagepolicies -setStoragePolicy -path / -policy ALL_SSD
获取存储策略如下：
hdfs storagepolicies -getStoragePolicy -path /