[
https://issues.apache.org/jira/browse/HDFS-9314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15023225#comment-15023225
]
Xiao Chen commented on HDFS-9314:
---------------------------------
Thanks [~mingma], good point on {{verifyBlockPlacement}}!
It's true that {{BlockPlacementPolicyWithNodeGroup}} does not override
{{verifyBlockPlacement}}, but
{{BlockPlacementPolicyWithNodeGroup#pickupReplicaSet}} favors node group name
when choosing replicas for delete. I'm not sure replacing it with default is
better, or adding {{BlockPlacementPolicyWithNodeGroup#verifyBlockPlacement}}.
Do you think it's safe to remove it? Perhaps that's a separate discussion...
Also adding original author [~djp] for more insights.
> Improve BlockPlacementPolicyDefault's picking of excess replicas
> ----------------------------------------------------------------
>
> Key: HDFS-9314
> URL: https://issues.apache.org/jira/browse/HDFS-9314
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Ming Ma
> Assignee: Xiao Chen
> Attachments: HDFS-9314.001.patch, HDFS-9314.002.patch,
> HDFS-9314.003.patch, HDFS-9314.004.patch, HDFS-9314.005.patch,
> HDFS-9314.006.patch
>
>
> The test case used in HDFS-9313 identified NullPointerException as well as
> the limitation of excess replica picking. If the current replicas are on
> {SSD(rack r1), DISK(rack 2), DISK(rack 3), DISK(rack 3)} and the storage
> policy changes to HOT_STORAGE_POLICY_ID, BlockPlacementPolicyDefault's won't
> be able to delete SSD replica.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
