[
https://issues.apache.org/jira/browse/HDFS-15759?focusedWorklogId=568303&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-568303
]
ASF GitHub Bot logged work on HDFS-15759:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 18/Mar/21 12:26
Start Date: 18/Mar/21 12:26
Worklog Time Spent: 10m
Work Description: touchida commented on a change in pull request #2585:
URL: https://github.com/apache/hadoop/pull/2585#discussion_r596820273
##########
File path:
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestReconstructStripedFileWithValidator.java
##########
@@ -0,0 +1,98 @@
+/**
+ * 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;
+
+import org.apache.hadoop.hdfs.server.datanode.DataNodeFaultInjector;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.nio.ByteBuffer;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * This test extends {@link TestReconstructStripedFile} to test
+ * ec reconstruction validation.
+ */
+public class TestReconstructStripedFileWithValidator
+ extends TestReconstructStripedFile {
+ private static final Logger LOG =
+ LoggerFactory.getLogger(TestReconstructStripedFileWithValidator.class);
+
+ public TestReconstructStripedFileWithValidator() {
+ LOG.info("run {} with validator.",
+ TestReconstructStripedFileWithValidator.class.getSuperclass()
+ .getSimpleName());
+ }
+
+ /**
+ * This test injects data pollution into decoded outputs once.
+ * When validation enabled, the first reconstruction task should fail
+ * in the validation, but the data will be recovered correctly
+ * by the next task.
+ * On the other hand, when validation disabled, the first reconstruction task
+ * will succeed and then lead to data corruption.
+ */
+ @Test(timeout = 120000)
+ public void testValidatorWithBadDecoding()
+ throws Exception {
+ DataNodeFaultInjector oldInjector = DataNodeFaultInjector.get();
+ DataNodeFaultInjector badDecodingInjector = new DataNodeFaultInjector() {
+ private final AtomicBoolean flag = new AtomicBoolean(false);
+
+ @Override
+ public void badDecoding(ByteBuffer[] outputs) {
+ if (!flag.get()) {
+ for (ByteBuffer output : outputs) {
+ output.mark();
+ output.put((byte) (output.get(output.position()) + 1));
+ output.reset();
+ }
+ }
+ flag.set(true);
+ }
+ };
+ DataNodeFaultInjector.set(badDecodingInjector);
+ int fileLen =
+ (getEcPolicy().getNumDataUnits() + getEcPolicy().getNumParityUnits())
+ * getBlockSize() + getBlockSize() / 10;
+ try {
+ assertFileBlocksReconstruction(
+ "/testValidatorWithBadDecoding",
+ fileLen,
+ ReconstructionType.DataOnly,
+ getEcPolicy().getNumParityUnits());
Review comment:
@runitao Agree!
I'm now considering to check the metric that I mentioned at
https://github.com/apache/hadoop/pull/2585#discussion_r596818639.
If you know an another idea, please let me know.
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Issue Time Tracking
-------------------
Worklog Id: (was: 568303)
Time Spent: 5h 20m (was: 5h 10m)
> EC: Verify EC reconstruction correctness on DataNode
> ----------------------------------------------------
>
> Key: HDFS-15759
> URL: https://issues.apache.org/jira/browse/HDFS-15759
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: datanode, ec, erasure-coding
> Affects Versions: 3.4.0
> Reporter: Toshihiko Uchida
> Assignee: Toshihiko Uchida
> Priority: Major
> Labels: pull-request-available
> Time Spent: 5h 20m
> Remaining Estimate: 0h
>
> EC reconstruction on DataNode has caused data corruption: HDFS-14768,
> HDFS-15186 and HDFS-15240. Those issues occur under specific conditions and
> the corruption is neither detected nor auto-healed by HDFS. It is obviously
> hard for users to monitor data integrity by themselves, and even if they find
> corrupted data, it is difficult or sometimes impossible to recover them.
> To prevent further data corruption issues, this feature proposes a simple and
> effective way to verify EC reconstruction correctness on DataNode at each
> reconstruction process.
> It verifies correctness of outputs decoded from inputs as follows:
> 1. Decoding an input with the outputs;
> 2. Compare the decoded input with the original input.
> For instance, in RS-6-3, assume that outputs [d1, p1] are decoded from inputs
> [d0, d2, d3, d4, d5, p0]. Then the verification is done by decoding d0 from
> [d1, d2, d3, d4, d5, p1], and comparing the original and decoded data of d0.
> When an EC reconstruction task goes wrong, the comparison will fail with high
> probability.
> Then the task will also fail and be retried by NameNode.
> The next reconstruction will succeed if the condition triggered the failure
> is gone.
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