[jira] [Commented] (HBASE-5074) support checksums in HBase block cache

["Phabricator (Commented) (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-5074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13195774#comment-13195774 ] 

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

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

  Good job, Dhruba.

  I like this comment from HFileSystem:

  + * In future, if we want to make hlogs be in a different filesystem,
  + * this is the place to make it happen.

  I only see one setVerifyChecksum() call in the HFileSystem ctor.
  The readfs is used by createReaderWithEncoding().

  Shall we give readfs more flexibility where checksum verification can be configured dynamically ?

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
>
>
> 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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