org.apache.hadoop.hdfs.protocol.HdfsConstants Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hdfs.protocol;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.HdfsConfiguration;
/************************************
* Some handy constants
*
************************************/
@InterfaceAudience.Private
public class HdfsConstants {
/* Hidden constructor */
protected HdfsConstants() {
}
/**
* HDFS Protocol Names:
*/
public static final String CLIENT_NAMENODE_PROTOCOL_NAME =
"org.apache.hadoop.hdfs.protocol.ClientProtocol";
public static final String CLIENT_DATANODE_PROTOCOL_NAME =
"org.apache.hadoop.hdfs.protocol.ClientDatanodeProtocol";
public static int MIN_BLOCKS_FOR_WRITE = 5;
// Long that indicates "leave current quota unchanged"
public static final long QUOTA_DONT_SET = Long.MAX_VALUE;
public static final long QUOTA_RESET = -1L;
//
// Timeouts, constants
//
public static final long LEASE_SOFTLIMIT_PERIOD = 60 * 1000;
public static final long LEASE_HARDLIMIT_PERIOD = 60 * LEASE_SOFTLIMIT_PERIOD;
public static final long LEASE_RECOVER_PERIOD = 10 * 1000; // in ms
// We need to limit the length and depth of a path in the filesystem.
// HADOOP-438
// Currently we set the maximum length to 8k characters and the maximum depth
// to 1k.
public static int MAX_PATH_LENGTH = 8000;
public static int MAX_PATH_DEPTH = 1000;
// TODO [email protected]: should be conf injected?
public static final int DEFAULT_DATA_SOCKET_SIZE = 128 * 1024;
public static final int IO_FILE_BUFFER_SIZE = new HdfsConfiguration().getInt(
DFSConfigKeys.IO_FILE_BUFFER_SIZE_KEY,
DFSConfigKeys.IO_FILE_BUFFER_SIZE_DEFAULT);
// Used for writing header etc.
public static final int SMALL_BUFFER_SIZE = Math.min(IO_FILE_BUFFER_SIZE / 2,
512);
public static final int BYTES_IN_INTEGER = Integer.SIZE / Byte.SIZE;
// SafeMode actions
public static enum SafeModeAction {
SAFEMODE_LEAVE, SAFEMODE_ENTER, SAFEMODE_GET;
}
// type of the datanode report
public static enum DatanodeReportType {
ALL, LIVE, DEAD
}
// An invalid transaction ID that will never be seen in a real namesystem.
public static final long INVALID_TXID = -12345;
/**
* Distributed upgrade actions:
*
* 1. Get upgrade status. 2. Get detailed upgrade status. 3. Proceed with the
* upgrade if it is stuck, no matter what the status is.
*/
public static enum UpgradeAction {
GET_STATUS, DETAILED_STATUS, FORCE_PROCEED;
}
/**
* URI Scheme for hdfs://namenode/ URIs.
*/
public static final String HDFS_URI_SCHEME = "hdfs";
/**
* A prefix put before the namenode URI inside the "service" field
* of a delgation token, indicating that the URI is a logical (HA)
* URI.
*/
public static final String HA_DT_SERVICE_PREFIX = "ha-hdfs:";
/**
* Please see {@link LayoutVersion} on adding new layout version.
*/
public static final int LAYOUT_VERSION = LayoutVersion
.getCurrentLayoutVersion();
}