[
https://issues.apache.org/jira/browse/HDFS-16613?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17550782#comment-17550782
]
caozhiqiang edited comment on HDFS-16613 at 6/7/22 3:46 AM:
------------------------------------------------------------
In my cluster tests, the following optimizations would maximize the IO
performance of the decommissioning DN. And the time spend by decommissioning a
DN reduced from 3 hours to half an hour.
# Add this patch
# Increase the value of dfs.namenode.replication.max-streams-hard-limit
# Decrease the value of dfs.namenode.reconstruction.pending.timeout-sec to
shorten the time interval for checking pendingReconstructions.
!image-2022-06-07-11-46-42-389.png|width=552,height=165!
was (Author: caozhiqiang):
In my cluster tests, the following optimizations would maximize the IO
performance of the decommissioning DN. And the time spend by decommissioning a
DN reduced from 3 hours to half an hour.
# Add this patch
# Increase the value of dfs.namenode.replication.max-streams-hard-limit
# Decrease the value of dfs.namenode.reconstruction.pending.timeout-sec to
shorten the time interval for checking pendingReconstructions.
> EC: Improve performance of decommissioning dn with many ec blocks
> -----------------------------------------------------------------
>
> Key: HDFS-16613
> URL: https://issues.apache.org/jira/browse/HDFS-16613
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: ec, erasure-coding, namenode
> Affects Versions: 3.4.0
> Reporter: caozhiqiang
> Assignee: caozhiqiang
> Priority: Major
> Labels: pull-request-available
> Attachments: image-2022-06-07-11-46-42-389.png
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> In a hdfs cluster with a lot of EC blocks, decommission a dn is very slow.
> The reason is unlike replication blocks can be replicated from any dn which
> has the same block replication, the ec block have to be replicated from the
> decommissioning dn.
> The configurations dfs.namenode.replication.max-streams and
> dfs.namenode.replication.max-streams-hard-limit will limit the replication
> speed, but increase these configurations will create risk to the whole
> cluster's network. So it should add a new configuration to limit the
> decommissioning dn, distinguished from the cluster wide max-streams limit.
--
This message was sent by Atlassian Jira
(v8.20.7#820007)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
