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https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15869330#comment-15869330
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Hadoop QA commented on HDFS-11402:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
35s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 3 new or modified test
files. {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 16m
56s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
58s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
43s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
13s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
18s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 1m
59s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
49s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
11s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
0s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
0s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
40s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
5s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
14s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 1m
59s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
39s{color} | {color:green} the patch passed {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 92m 42s{color}
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
27s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}124m 49s{color} |
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|| Reason || Tests ||
| Failed junit tests | hadoop.tools.TestHdfsConfigFields |
| | hadoop.hdfs.TestRollingUpgrade |
| | hadoop.hdfs.server.datanode.TestDataNodeVolumeFailureReporting |
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|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:a9ad5d6 |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12852975/HDFS-11402.01.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle |
| uname | Linux 043c43761295 3.13.0-107-generic #154-Ubuntu SMP Tue Dec 20
09:57:27 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / a136936 |
| Default Java | 1.8.0_121 |
| findbugs | v3.0.0 |
| unit |
https://builds.apache.org/job/PreCommit-HDFS-Build/18386/artifact/patchprocess/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-HDFS-Build/18386/testReport/ |
| modules | C: hadoop-hdfs-project/hadoop-hdfs U:
hadoop-hdfs-project/hadoop-hdfs |
| Console output |
https://builds.apache.org/job/PreCommit-HDFS-Build/18386/console |
| Powered by | Apache Yetus 0.5.0-SNAPSHOT http://yetus.apache.org |
This message was automatically generated.
> HDFS Snapshots should capture point-in-time copies of OPEN files
> ----------------------------------------------------------------
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
> Affects Versions: 2.6.0
> Reporter: Manoj Govindassamy
> Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1-----------T2-------------T3----------------T4------>
> |-----------------------Snap1----------Snap2-------------Snap3--->
> |---File1.open---write---------write-----------close------------->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
> <File1 write completed and closed>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
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