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https://issues.apache.org/jira/browse/HBASE-5074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13218423#comment-13218423
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dhruba borthakur commented on HBASE-5074:
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@Stack: I am pretty sure that the feature is on by default (but let me check
and get back to you). Regarding the exception message about CRC32C, the Enum is
trying to create this object but failing to do so because the Hadoop library in
Hadoop 1.0 does not have support for this one (Hadop 2.0 supports CRC32C). The
reason I kept that is because people who might already be experimenting with
Hadoop 2.0 will get this support out-of-the-box. But I agree that it will be
good to get rid of this exception message at startup. Do you have any
suggestions on this one?
@Todd: will take your excellent suggestion and make the majorVersion inside
HFileBlock as a "static". Thanks.
@Ted: Thanks for your comments. Will try to gather metrics in my cluster and
post to this JIRA.
> 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, D1521.10.patch,
> D1521.10.patch, D1521.10.patch, D1521.10.patch, D1521.10.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, D1521.9.patch,
> D1521.9.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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