public void startSyncFromHdfs(final Runnable callback) throws IOException
{
Configuration conf=params.getConf();
CRC32 crc32 = new CRC32();
crc32.update(String.valueOf(java.util.UUID.randomUUID().toString()).getBytes());
Long uuid=crc32.getValue();
String pathname=String.valueOf(fmt.format(new Date())+"_"+status.uniqIndex.incrementAndGet()) + "_" + uuid;
final Path localHdfsRecover=new Path(new Path(params.getIndexMalloc(pathname.hashCode()),"realtime_hdfs_recover"),pathname);
final Path hdfsRealtime=new Path(params.hdfsPath,"realtime");