The following code in Datanode.java
causes check disk to happen in case of any errors during invalidate.
We have seen errors like :
2013-03-02 00:08:28,849 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Unexpected error trying to delete block blk_-2973118207682441648_225738165. BlockInfo not found in volumeMap.
And all such errors trigger check disk, making the clients timeout.