[
https://issues.apache.org/jira/browse/HDFS-5757?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Ming Ma updated HDFS-5757:
--------------------------
Assignee: Ming Ma
Status: Patch Available (was: Open)
> Decommisson lots of nodes at the same time could slow down NN
> -------------------------------------------------------------
>
> Key: HDFS-5757
> URL: https://issues.apache.org/jira/browse/HDFS-5757
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Reporter: Ming Ma
> Assignee: Ming Ma
> Attachments: HDFS-5757.patch
>
>
> Sometimes we need to decomm a whole rack of nodes at the same time. When the
> decomm is in process; NN is slow.
> The reason is when DecommissionManager checks the decomm status, it acquires
> namesystem's writer lock and iterates through all DNs; for each DN that is in
> decommissioning state, it check if replication is done for all the blocks on
> the machine via blockManager.isReplicationInProgress; for large cluster; the
> number of blocks on the machine could be big.
> The fix could be to have DecommissionManager check for several
> decomm-in-progress nodes each time it aquires namesystem's writer lock.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
