Many resources are needed to download a project. Please understand that we have to compensate our server costs. Thank you in advance. Project price only 1 $
You can buy this project and download/modify it how often you want.
/**
* 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.server.namenode;
import java.util.HashMap;
import java.util.Map;
import java.util.SortedSet;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hdfs.protocol.LayoutVersion;
import org.apache.hadoop.hdfs.protocol.LayoutVersion.FeatureInfo;
import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature;
@InterfaceAudience.Private
public class NameNodeLayoutVersion {
/** Build layout version and corresponding feature matrix */
public final static Map> FEATURES
= new HashMap>();
public static final int CURRENT_LAYOUT_VERSION
= LayoutVersion.getCurrentLayoutVersion(Feature.values());
public static final int MINIMUM_COMPATIBLE_LAYOUT_VERSION
= LayoutVersion.getMinimumCompatibleLayoutVersion(Feature.values());
static {
LayoutVersion.updateMap(FEATURES, LayoutVersion.Feature.values());
LayoutVersion.updateMap(FEATURES, NameNodeLayoutVersion.Feature.values());
}
public static SortedSet getFeatures(int lv) {
return FEATURES.get(lv);
}
public static boolean supports(final LayoutFeature f, final int lv) {
return LayoutVersion.supports(FEATURES, f, lv);
}
/**
* Enums for features that change the layout version.
*
* To add a new layout version:
*
*
Define a new enum constant with a short enum name, the new layout version
* and description of the added feature.
*
When adding a layout version with an ancestor that is not same as
* its immediate predecessor, use the constructor where a specific ancestor
* can be passed.
*
*
Specify a minimum compatible layout version. The minimum compatible
* layout version is the earliest prior version to which a downgrade is
* possible after initiating rolling upgrade. If the feature cannot satisfy
* compatibility with any prior version, then set its minimum compatible
* lqyout version to itself to indicate that downgrade is impossible.
* Satisfying compatibility might require adding logic to the new feature to
* reject operations or handle them differently while rolling upgrade is in
* progress. In general, it's possible to satisfy compatiblity for downgrade
* if the new feature just involves adding new edit log ops. Deeper
* structural changes, such as changing the way we place files in the metadata
* directories, might be incompatible. Feature implementations should strive
* for compatibility, because it's in the best interest of our users to
* support downgrade.
*
*/
public enum Feature implements LayoutFeature {
ROLLING_UPGRADE(-55, -53, -55, "Support rolling upgrade", false),
EDITLOG_LENGTH(-56, -56, "Add length field to every edit log op"),
XATTRS(-57, -57, "Extended attributes"),
CREATE_OVERWRITE(-58, -58, "Use single editlog record for " +
"creating file with overwrite"),
XATTRS_NAMESPACE_EXT(-59, -59, "Increase number of xattr namespaces"),
BLOCK_STORAGE_POLICY(-60, -60, "Block Storage policy"),
TRUNCATE(-61, -61, "Truncate"),
APPEND_NEW_BLOCK(-62, -61, "Support appending to new block"),
QUOTA_BY_STORAGE_TYPE(-63, -61, "Support quota for specific storage types"),
ERASURE_CODING(-64, -61, "Support erasure coding"),
EXPANDED_STRING_TABLE(-65, -61, "Support expanded string table in fsimage");
private final FeatureInfo info;
/**
* Feature that is added at layout version {@code lv} - 1.
* @param lv new layout version with the addition of this feature
* @param minCompatLV minimium compatible layout version
* @param description description of the feature
*/
Feature(final int lv, int minCompatLV, final String description) {
this(lv, lv + 1, minCompatLV, description, false);
}
/**
* NameNode feature that is added at layout version {@code ancestoryLV}.
* @param lv new layout version with the addition of this feature
* @param ancestorLV layout version from which the new lv is derived from.
* @param minCompatLV minimum compatible layout version
* @param description description of the feature
* @param reserved true when this is a layout version reserved for previous
* versions
* @param features set of features that are to be enabled for this version
*/
Feature(final int lv, final int ancestorLV, int minCompatLV,
final String description, boolean reserved, Feature... features) {
info = new FeatureInfo(lv, ancestorLV, minCompatLV, description, reserved,
features);
}
@Override
public FeatureInfo getInfo() {
return info;
}
}
}
