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https://issues.apache.org/jira/browse/HBASE-5074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13217749#comment-13217749
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Zhihong Yu commented on HBASE-5074:
-----------------------------------
The exception about org.apache.hadoop.util.PureJavaCrc32C not found should be
normal - it was WARN.
It was produced by ChecksumType ctor for this:
{code}
CRC32C((byte)2) {
{code}
Metrics should be collected on the cluster to see the difference.
> 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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