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https://issues.apache.org/jira/browse/HADOOP-3860?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12620141#action_12620141
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dhruba borthakur commented on HADOOP-3860:
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Hi Konstantin,
Great analysis. I completely agree with you that coarse-grain locking for the
namenode should not be impacting scalability of opens and creates. It is the
disk sync times that really matters. BTW, when you ran the test on a single
disk on local drive, did you see the disk max-out on IO? You said that 5710
creates occured, the limitation being CPU on the machine or disk IO contention?
Also, I had a patch HADOOP-2330 that pre-allocated transaction log. If I had
seen this JIRA earlier, i would have requested you to see if you could repeat
the exact same test on the same hardware with this patch. This patch
pre-allocates the transaction log in large chunks.
> Compare name-node performance when journaling is performed into local
> hard-drives or nfs.
> -----------------------------------------------------------------------------------------
>
> Key: HADOOP-3860
> URL: https://issues.apache.org/jira/browse/HADOOP-3860
> Project: Hadoop Core
> Issue Type: Improvement
> Affects Versions: 0.19.0
> Reporter: Konstantin Shvachko
> Assignee: Konstantin Shvachko
> Fix For: 0.19.0
>
> Attachments: NNThruputMoreOps.patch
>
>
> The goal of this issue is to measure how the name-node performance depends on
> where the edits log is written to.
> Three types of the journal storage should be evaluated:
> # local hard drive;
> # remote drive mounted via nfs;
> # nfs filer.
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