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https://issues.apache.org/jira/browse/HBASE-5074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13211167#comment-13211167
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Phabricator commented on HBASE-5074:
------------------------------------
stack has commented on the revision "[jira] [HBASE-5074] Support checksums in
HBase block cache".
Got to the 20% stage.
Whats the status of this patch Dhruba? Are you running it anywhere?
INLINE COMMENTS
src/main/java/org/apache/hadoop/hbase/io/hfile/ChecksumUtil.java:46 Great
comments
src/main/java/org/apache/hadoop/hbase/io/hfile/ChecksumUtil.java:84 The value
returned is a long. Why convert to an int?
src/main/java/org/apache/hadoop/hbase/io/hfile/ChecksumUtil.java:18 I think
its good that this utility is in this pacage since it seems particular to this
package. At first I thought it general utility... there is some but mostly its
about this feature it seems.
src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java:205 Do you want to
doc that a get resets count to zero?
src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java:462 Yeah, its hard
to contain the checksumming feature to just a few places; it leaks out all over
io.hfile. Thats fine.
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, D1521.4.patch, D1521.4.patch,
> D1521.5.patch, D1521.5.patch, D1521.6.patch, D1521.6.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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