hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Andrew Wang (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-6581) Write to single replica in memory
Date Wed, 24 Sep 2014 18:12:36 GMT

    [ https://issues.apache.org/jira/browse/HDFS-6581?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14146647#comment-14146647
] 

Andrew Wang commented on HDFS-6581:
-----------------------------------

Thanks for running these numbers Arpit. To convert into MB/s, it seems like we're going from
280 or 292 MB/s baseline to 455 or 487MBs with csums off.

Are you aware of any further copies that can be eliminated in DTP, or via something like short-circuit
writes? I'd be satisfied regarding the merge if we had a pretty good estimate of the perf
after such improvements are made. Saying that we could go from e.g. 4 copies to 2 copies would
suffice for this, better would be results from a prototype.

> Write to single replica in memory
> ---------------------------------
>
>                 Key: HDFS-6581
>                 URL: https://issues.apache.org/jira/browse/HDFS-6581
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: datanode
>            Reporter: Arpit Agarwal
>            Assignee: Arpit Agarwal
>         Attachments: HDFS-6581.merge.01.patch, HDFS-6581.merge.02.patch, HDFS-6581.merge.03.patch,
HDFS-6581.merge.04.patch, HDFS-6581.merge.05.patch, HDFS-6581.merge.06.patch, HDFS-6581.merge.07.patch,
HDFS-6581.merge.08.patch, HDFS-6581.merge.09.patch, HDFS-6581.merge.10.patch, HDFSWriteableReplicasInMemory.pdf,
Test-Plan-for-HDFS-6581-Memory-Storage.pdf
>
>
> Per discussion with the community on HDFS-5851, we will implement writing to a single
replica in DN memory via DataTransferProtocol.
> This avoids some of the issues with short-circuit writes, which we can revisit at a later
time.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message