Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: hdfs-issues@hadoop.apache.org
Date: Fri, 20 Nov 2015 00:02:11 +0000 (UTC)
From: "Xiao Chen (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
Message-ID: <JIRA.12908085.1445909088000.130766.1447977731035@Atlassian.JIRA>
In-Reply-To: <JIRA.12908085.1445909088000@Atlassian.JIRA>
References: <JIRA.12908085.1445909088000@Atlassian.JIRA>
 <JIRA.12908085.1445909088376@arcas>
Subject: [jira] [Commented] (HDFS-9314) Improve
 BlockPlacementPolicyDefault's picking of excess replicas
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/HDFS-9314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15014801#comment-15014801 ] 

Xiao Chen commented on HDFS-9314:
---------------------------------

Thanks [~mingma] for the review, I'll be working on the next rev.
1 quick clarification: I thought about passing in {{rackMap}}, but that needs to add the extra parameter to both {{chooseReplicaToDelete}} and {{pickupReplicaSet}}.
- I guess {{@VisibleForTesting public chooseReplicaToDelete}} should be fine. 
- But changing the {{protected pickupReplicaSet}} would require modifying all subclasses of {{BlockPlacementPolicyDefault}}, which is marked as {{@InterfaceAudience.Private}} so [no external subclasses are expected|https://hadoop.apache.org/docs/r2.7.1/api/org/apache/hadoop/classification/InterfaceAudience.html]. So we'll just update all usages in current code and not worry about compatibility.

Are we on the same page here?

> 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
>
>
> 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)