測試 hdfs - fuse

• 已知問題(讀與寫的效能都比原生dfsclient低)

1. if you alias ls to ls --color=auto and try listing a directory with lots (over thousands) of files, expect it to be slow and at 10s of thousands, expect it to be very very slow. This is because --color=auto causes ls to stat every file in the directory. Since fuse-dfs does not cache attribute entries when doing a readdir, this is very slow. see HADOOP-3797

2. Writes are approximately 33% slower than the DFSClient. TBD how to optimize this. see: HADOOP-3805 - try using -obig_writes if on a >2.6.26 kernel, should perform much better since bigger writes implies less context switching.

3. Reads are ~20-30% slower even with the read buffering.