public FileSystem getFileSystem() {
        if (fileSystem != null) {
            return fileSystem;
        }

        URI uri = URI.create(getFileSystemConnection());
        Configuration config = new Configuration();
        config.set("fs.hdfs.impl", DistributedFileSystem.class.getName());
        try {
            fileSystem = FileSystem.get(uri, config);
        } catch (IOException e) {
            throw new RuntimeException("Initialize file system failed!", e);
        }
        return fileSystem;
    }
The path where realtime segments declare.
<pre>
    .../rt/table/tableA/host0/seg0_0 ... segN_0
    .../rt/table/tableA/host1/seg0_1 ... segN_1
</pre>
indexr-server/src/main/java/io/indexr/server/IndexRConfig.java