if (blockSize == 0)
blockSize = (long) (conf.getConfiguration().getMemoryInBytes(Property.TSERV_WALOG_MAX_SIZE) * 1.1);
if (conf.getConfiguration().getBoolean(Property.TSERV_WAL_SYNC))
logFile = fs.createSyncable(new Path(logPath), 0, replication, blockSize);
else
logFile = fs.create(new Path(logPath), true, 0, replication, blockSize);
String syncMethod = conf.getConfiguration().get(Property.TSERV_WAL_SYNC_METHOD);
try {
// hsync: send data to datanodes and sync the data to disk
sync = logFile.getClass().getMethod(syncMethod);