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Date: Tue, 7 Feb 2012 02:45:00 +0000 (UTC)
From: "Phabricator (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=13202024#comment-13202024 ] 

Phabricator commented on HBASE-5074:
------------------------------------

tedyu has commented on the revision "[jira] [HBASE-5074] Support checksums in HBase block cache".

INLINE COMMENTS
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java:160 I don't see PureJavaCrc32 in hadoop 1.0 either.
  I think it would be nice to default to the best checksum class.
  src/main/java/org/apache/hadoop/hbase/regionserver/Store.java:257 Would hbase.hstore.checksum.algo be a better name for this config parameter ?

REVISION DETAIL
  https://reviews.facebook.net/D1521

                
> 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
>
>
> 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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