[jira] [Commented] (HDFS-8710) Always read DU value from the cached dfsUsed file on datanode startup
[ https://issues.apache.org/jira/browse/HDFS-8710?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14613975#comment-14613975 ] Allen Wittenauer commented on HDFS-8710: bq. In a large cluster, the DU can even cost several or tens of minutes, which slows down startup speed of the whole cluster, so quick startup is necessary. You don't need to tell me about large clusters. If start up time is a concern, then one should be using rolling upgrade or some other decayed stop/start on DN bring up. -1 on the change. It's ultimately confusing to operations folks to have to wait 10 minutes for their change to take place. Closing as won't fix. Always read DU value from the cached dfsUsed file on datanode startup --- Key: HDFS-8710 URL: https://issues.apache.org/jira/browse/HDFS-8710 Project: Hadoop HDFS Issue Type: Improvement Reporter: Xinwei Qin Assignee: Xinwei Qin Attachments: HDFS-8710.001.patch Currently, DataNode will cache DU value in dfsUsed file termly. When DataNode starts or restarts, it will read in the cached DU value from dfsUsed file if the value is less than 600 seconds old, otherwise, it will run DU command, which is a very time-consuming operation(may up to dozens of minutes) when DataNode has huge number of blocks. Since slight imprecision of dfsUsed is not critical, and the DU value will be updated every 600 seconds (the default DU interval) after DataNode started, we can always read DU value from the cached file (Regardless of whether this value is less than 600 seconds old or not) and skip DU operation on DataNode startup to significantly shorten the startup time. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (HDFS-8710) Always read DU value from the cached dfsUsed file on datanode startup
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https://issues.apache.org/jira/browse/HDFS-8710?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14613692#comment-14613692
]
Hadoop QA commented on HDFS-8710:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:red}-1{color} | pre-patch | 17m 53s | Pre-patch trunk has 1 extant
Findbugs (version 3.0.0) warnings. |
| {color:green}+1{color} | @author | 0m 0s | The patch does not contain any
@author tags. |
| {color:red}-1{color} | tests included | 0m 0s | The patch doesn't appear
to include any new or modified tests. Please justify why no new tests are
needed for this patch. Also please list what manual steps were performed to
verify this patch. |
| {color:green}+1{color} | javac | 7m 33s | There were no new javac warning
messages. |
| {color:green}+1{color} | javadoc | 9m 40s | There were no new javadoc
warning messages. |
| {color:green}+1{color} | release audit | 0m 22s | The applied patch does
not increase the total number of release audit warnings. |
| {color:green}+1{color} | checkstyle | 2m 20s | There were no new checkstyle
issues. |
| {color:green}+1{color} | whitespace | 0m 0s | The patch has no lines that
end in whitespace. |
| {color:green}+1{color} | install | 1m 35s | mvn install still works. |
| {color:green}+1{color} | eclipse:eclipse | 0m 33s | The patch built with
eclipse:eclipse. |
| {color:green}+1{color} | findbugs | 3m 19s | The patch does not introduce
any new Findbugs (version 3.0.0) warnings. |
| {color:green}+1{color} | native | 3m 16s | Pre-build of native portion |
| {color:red}-1{color} | hdfs tests | 158m 10s | Tests failed in hadoop-hdfs. |
| | | 204m 44s | |
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|| Reason || Tests ||
| Failed unit tests |
hadoop.hdfs.server.balancer.TestBalancerWithMultipleNameNodes |
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|| Subsystem || Report/Notes ||
| Patch URL |
http://issues.apache.org/jira/secure/attachment/12743258/HDFS-8710.001.patch |
| Optional Tests | javadoc javac unit findbugs checkstyle |
| git revision | trunk / 2eae130 |
| Pre-patch Findbugs warnings |
https://builds.apache.org/job/PreCommit-HDFS-Build/11571/artifact/patchprocess/trunkFindbugsWarningshadoop-hdfs.html
|
| hadoop-hdfs test log |
https://builds.apache.org/job/PreCommit-HDFS-Build/11571/artifact/patchprocess/testrun_hadoop-hdfs.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-HDFS-Build/11571/testReport/ |
| Java | 1.7.0_55 |
| uname | Linux asf909.gq1.ygridcore.net 3.13.0-36-lowlatency #63-Ubuntu SMP
PREEMPT Wed Sep 3 21:56:12 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux |
| Console output |
https://builds.apache.org/job/PreCommit-HDFS-Build/11571/console |
This message was automatically generated.
Always read DU value from the cached dfsUsed file on datanode startup
---
Key: HDFS-8710
URL: https://issues.apache.org/jira/browse/HDFS-8710
Project: Hadoop HDFS
Issue Type: Improvement
Reporter: Xinwei Qin
Assignee: Xinwei Qin
Attachments: HDFS-8710.001.patch
Currently, DataNode will cache DU value in dfsUsed file termly. When
DataNode starts or restarts, it will read in the cached DU value from
dfsUsed file if the value is less than 600 seconds old, otherwise, it will
run DU command, which is a very time-consuming operation(may up to dozens of
minutes) when DataNode has huge number of blocks.
Since slight imprecision of dfsUsed is not critical, and the DU value will be
updated every 600 seconds (the default DU interval) after DataNode started,
we can always read DU value from the cached file (Regardless of whether this
value is less than 600 seconds old or not) and skip DU operation on DataNode
startup to significantly shorten the startup time.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
[jira] [Commented] (HDFS-8710) Always read DU value from the cached dfsUsed file on datanode startup
[
https://issues.apache.org/jira/browse/HDFS-8710?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14613014#comment-14613014
]
Xinwei Qin commented on HDFS-8710:
---
[~aw], thanks for your comment.
The du value will be recalculated after 600 seconds, we don't need to
calculated a precise value on startup. The current project cannot also
recalculate du value when the disk structure changed if the {{dfsUsed}} value
is less than 600 seconds old.
In a large cluster, the DU can even cost several or tens of minutes, which
slows down startup speed of the whole cluster, so quick startup is necessary.
Maybe always skip DU is radical, add a quick-restart configuration(default is
true to skip DU) for datanode is more reasonable, when disk structure is
changed, user can turn off quick-restart configuration to trigger DU to
recalculate dfsused value. Any thoughts?
Always read DU value from the cached dfsUsed file on datanode startup
---
Key: HDFS-8710
URL: https://issues.apache.org/jira/browse/HDFS-8710
Project: Hadoop HDFS
Issue Type: Improvement
Reporter: Xinwei Qin
Assignee: Xinwei Qin
Attachments: HDFS-8710.001.patch
Currently, DataNode will cache DU value in dfsUsed file termly. When
DataNode starts or restarts, it will read in the cached DU value from
dfsUsed file if the value is less than 600 seconds old, otherwise, it will
run DU command, which is a very time-consuming operation(may up to dozens of
minutes) when DataNode has huge number of blocks.
Since slight imprecision of dfsUsed is not critical, and the DU value will be
updated every 600 seconds (the default DU interval) after DataNode started,
we can always read DU value from the cached file (Regardless of whether this
value is less than 600 seconds old or not) and skip DU operation on DataNode
startup to significantly shorten the startup time.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
[jira] [Commented] (HDFS-8710) Always read DU value from the cached dfsUsed file on datanode startup
[ https://issues.apache.org/jira/browse/HDFS-8710?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14612876#comment-14612876 ] Allen Wittenauer commented on HDFS-8710: On startup is exactly when you want the du to be recalculated because there is a good chance that the disk structure changed. Always read DU value from the cached dfsUsed file on datanode startup --- Key: HDFS-8710 URL: https://issues.apache.org/jira/browse/HDFS-8710 Project: Hadoop HDFS Issue Type: Improvement Reporter: Xinwei Qin Assignee: Xinwei Qin Attachments: HDFS-8710.001.patch Currently, DataNode will cache DU value in dfsUsed file termly. When DataNode starts or restarts, it will read in the cached DU value from dfsUsed file if the value is less than 600 seconds old, otherwise, it will run DU command, which is a very time-consuming operation(may up to dozens of minutes) when DataNode has huge number of blocks. Since slight imprecision of dfsUsed is not critical, and the DU value will be updated every 600 seconds (the default DU interval) after DataNode started, we can always read DU value from the cached file (Regardless of whether this value is less than 600 seconds old or not) and skip DU operation on DataNode startup to significantly shorten the startup time. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
