001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.hdfs.server.blockmanagement;
019    
020    import org.apache.hadoop.hdfs.protocol.ClientProtocol;
021    
022    /** Datanode statistics */
023    public interface DatanodeStatistics {
024    
025      /** @return the total capacity */
026      public long getCapacityTotal();
027    
028      /** @return the used capacity */
029      public long getCapacityUsed();
030    
031      /** @return the percentage of the used capacity over the total capacity. */
032      public float getCapacityUsedPercent();
033    
034      /** @return the remaining capacity */
035      public long getCapacityRemaining();
036    
037      /** @return the percentage of the remaining capacity over the total capacity. */
038      public float getCapacityRemainingPercent();
039    
040      /** @return the block pool used. */
041      public long getBlockPoolUsed();
042    
043      /** @return the percentage of the block pool used space over the total capacity. */
044      public float getPercentBlockPoolUsed();
045      
046      /** @return the total cache capacity of all DataNodes */
047      public long getCacheCapacity();
048    
049      /** @return the total cache used by all DataNodes */
050      public long getCacheUsed();
051    
052      /** @return the xceiver count */
053      public int getXceiverCount();
054    
055      /** @return average xceiver count for non-decommission(ing|ed) nodes */
056      public int getInServiceXceiverCount();
057      
058      /** @return number of non-decommission(ing|ed) nodes */
059      public int getNumDatanodesInService();
060      
061      /**
062       * @return the total used space by data nodes for non-DFS purposes
063       * such as storing temporary files on the local file system
064       */
065      public long getCapacityUsedNonDFS();
066    
067      /** The same as {@link ClientProtocol#getStats()}.
068       * The block related entries are set to -1.
069       */
070      public long[] getStats();
071    
072      /** @return the expired heartbeats */
073      public int getExpiredHeartbeats();
074    }