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Date: Thu, 23 Feb 2012 07:09:49 +0000 (UTC)
From: "dhruba borthakur (Commented) (JIRA)" <jira@apache.org>
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Subject: [jira] [Commented] (HBASE-5074) support checksums in HBase block
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    [ https://issues.apache.org/jira/browse/HBASE-5074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13214402#comment-13214402 ] 

dhruba borthakur commented on HBASE-5074:
-----------------------------------------

@Stack: I am running it on a very small cluster, but will deploy it on a larger cluster next week. Please hold off committing this one till my larger-cluster-tests pass.

I will also address Stack's and Ted's review comments in the next version of my patch
                
> support checksums in HBase block cache
> --------------------------------------
>
>                 Key: HBASE-5074
>                 URL: https://issues.apache.org/jira/browse/HBASE-5074
>             Project: HBase
>          Issue Type: Improvement
>          Components: regionserver
>            Reporter: dhruba borthakur
>            Assignee: dhruba borthakur
>         Attachments: D1521.1.patch, D1521.1.patch, D1521.2.patch, D1521.2.patch, D1521.3.patch, D1521.3.patch, D1521.4.patch, D1521.4.patch, D1521.5.patch, D1521.5.patch, D1521.6.patch, D1521.6.patch, D1521.7.patch, D1521.7.patch, D1521.8.patch, D1521.8.patch
>
>
> The current implementation of HDFS stores the data in one block file and the metadata(checksum) in another block file. This means that every read into the HBase block cache actually consumes two disk iops, one to the datafile and one to the checksum file. This is a major problem for scaling HBase, because HBase is usually bottlenecked on the number of random disk iops that the storage-hardware offers.

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